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date: 16 August 2017

The Concept of Deterrence and Deterrence Theory

Summary and Keywords

Deterrence is an old practice, readily defined and described, widely employed but unevenly effective and of questionable reliability. Elevated to prominence after World War II and the arrival of nuclear weapons, deterrence became the central recourse for sustaining international and internal security and stability among and within states in an era of serious conflict. With regard to the presence of nuclear weapons in particular but also to deal with non-nuclear violent conflict, deterrence has been employed to prevent (or at least limit) the destruction of states, societies, and ultimately humanity. The greatest success has been that no nuclear weapons have been used for destructive purposes since the end of World War II in 1945. Deterrence has been widely used below the nuclear level but with very uneven results.

Deterrence has been intensively studied and tested as to its use in terms of strategy in international relations, the maintenance of stability in international relations, the conduct of violence and warfare in both international and domestic contexts, and in political affairs. Since deterrence is the use of threats to block or reduce the inflicting of serious harm, the existence of capacities for inflicting harm are readily maintained and periodically applied, so available deterrence capabilities provide a degree of continuing concern and a regular desire to at least do away with nuclear weapons and threats. A brief period in the ending of the Cold War saw a serious effort to reduce the reliance on deterrence, particularly nuclear deterrence, in international politics but it was soon replaced by serious movement in the opposite direction. Yet efforts to reduce the need for and use of deterrence continue.

Extensive efforts have been applied in the development of theories of deterrence, particularly to generate empirical theory in order to better understand and apply deterrence but without arriving at widely accepted results. This is the result of the considerable complexity of the subject, the activity involved, and the behavior of the practitioners.

The conduct of deterrence is now broader and deeper than before. It is under greater pressure due to technological, political, and cultural developments, and operates in a much more elaborate overall environment including space, cyberspace, and oceanic environs. Thus the goal of developing effective empirical theory on deterrence remains, at various levels, still incompletely attained. The same is true of mastering deterrence in practice. Nevertheless, deterrence remains important and fascinating.

Keywords: deterrence, compellence, nuclear deterrence, general deterrence, immediate deterrence, extended deterrence, mutually assured destruction, credibility, stability, collective global security management, empirical international relations theory

Preliminary Comment

Deterrence is an old concept, with a modern name, in international politics. It has a long and varied history but is most notably associated with the threat and fear of war and how both can be manipulated and prevented. The study of deterrence still focuses on how to prevent being attacked by threatening the potential attacker with serious harm. But now a broader focus is called for to cover the expanding range of deterrence-related threats and activities involved. The core objective remains attack prevention, but deterrence is now also discussed as using other punitive steps, military and nonmilitary, to curtail threats and attacks—including even nonmilitary ones. It is a steadily growing field.

Thus deterrence can now be involved in many more kinds of situations. However, it emerged in modern history as associated with fending off violent attacks, i.e. via meeting a threat with a threat). If this effort does not work and an attack ensues, and the deterrer (and others) can then seek to inflict harm, another kind of deterrence, to try to halt the conflict. If that fails, trying to end the fighting may well continue via options other than deterrence such as surrender, appealing to other states for help, offering payoffs to the attacker; apologizing, requesting negotiations, . . . Another possibility is other states or actors using deterrence to intervene for various reasons: the conflict is generating an international economic slump; or it is producing a surge of refugees or the unavailability of valuable products; or it is producing interference from some unwanted party, and so on. Sometimes using deterrence to threaten incites or escalates conflict because a threatened state may feel insulted or request military help from others. Or the deterrence threat and attack might start an arms race.

Deterrence became the central preoccupation in international security because of World War II and the atom bombs dropped on Japan. The two bombs were so destructive that the possibility of another world war and more nuclear attacks made deterrence, and eventually deterrence theory, terribly important in offering hope of avoiding all that. Deterrence and deterrence theory would become vital for coping with the ensuing nuclear arms race and Cold War, and for handling conventional and lesser political and military conflicts. Deterrence and deterrence theory became the ultimate safeguard in international security affairs and helped discourage the building and spread of nuclear, chemical, and biological weapons via arms control. Also employed was a variant of deterrence, compellence, for preventing an opponent from continuing an attack or other harmful acts by threatening significant retaliation to “compel” potential aggressors into doing something they did not want to do, like abandoning a nuclear weapons development program or breaking off a war. Compellence and deterrence overlap, but compellence has been considered harder to use successfully.1

Deterrence has two broad categories—general and immediate; different in concept, definition, use, and time frame. General deterrence conveys a somewhat vague, broad, and often steadily continuous threat of retaliation for a possible future attack. Mounted to protect the deterring entity or others, it can also be similarly mounted by a collective actor such as NATO. In contrast, Immediate deterrence involves threatening retaliation because an attack is close at hand or in its early stages and has to be halted. General deterrence is therefore a much longer lasting, more common, and typically more durable phenomenon—it may even continue for decades. Immediate deterrence is scarier and more intense, typically brief in application or implementation. Both general and immediate deterrence can be used strategically or tactically.

Finally, it is noteworthy that deterrence is partly designed and mounted by the influence of its surrounding context, which helps shape why, where, and how it is needed and used. Shifts in context often seriously alter the nature of deterrence and may strongly affect how it works or fails.


In contemporary international politics deterrence operates at four levels of interactions among states and other groups. At the sub-state level deterrence may be involved in confronting serious, often violent, conflicts between notable groups—ethnic, political, religious, even criminal—outside or within a state, groups that sometimes extend into other states.2

The state level typically involves a state or several states in a conflict or conflicts in their neighborhood, such as interstate conflict (perhaps some fighting) over a border or a territory, or over who should dominate or own part of the ocean. Such conflicts can generate deterrence threats and actions, in reaction to or by leading toward violent struggles or battles, even more serious conflicts (a civil war, an insurgency, a conflict with terrorists), or one involving two or more states fighting—perhaps over how one state’s treatment of a group offends another state. Sometimes conflicts between or within states lead to serious threats of war, ongoing fighting, interrelated wars in the area that attract military intervention or threats of it from a region’s international or global system states even when the conflict is not highly important to them.3 Of the current fighting among or within states, this is the level where most such clashes are located and related deterrence efforts are actively employed, and is often a way states and/or groups conflictually interact, even in a more than two-party situation.

The third level involves conflicts between or among states or state groups of fairly notable actors in a regional or the global international system. These states typically have above average power, ambition, capabilities, and interests; they may even dominate their regional system. They may often face actual or potential threats. Sometimes such a state also has weak domestic underpinnings and serious domestic conflict; threats to the government, or domestic, political, and other elements weakening the country’s international status and relationships or its power and influence. These are countries like Iran, Brazil, Egypt, Nigeria, Thailand, Saudi Arabia, Indonesia, India, among others. The threats they face may include internal unrest, religious radicalism, economic collapse, coups, corruption, along with competition among the states themselves or with powerful members of the global system.

Fourth level conflicts involve powerful states, acting individually or with a group, having the ambitions, capabilities, resources, and interests to play a notable role in—even to dominate or seek to dominate—a major part of the international system. These great, or near great, powers and their conflicts seriously affect that system in varying ways. Fortunately, their conflicts now rarely develop into outright fighting. These states also take an interest in, intrude on, or otherwise try to affect other related conflicts or even each other’s internal conflicts. They have a profound interest in maintaining their autonomy, peace, and security so a deterrence posture toward threats or attacks is standard. Often they seek to enhance not only these goals but also other benefits: more territory, citizens, and resources perhaps, or to dominate nonthreatening neighbors and buffer areas they want to deter others from interfering with. Or perhaps just wanting to enhance their capacity to deter and defend.

At the international level and in some regions, states may cluster in groups, or alliances, to collectively bolster security. Or they may develop “balance of power” arrangements among themselves or vis-à-vis other groups of states to bolster their safety—arrangements typically related to deterrence practices. Here and at the regional level powerful states often seek to dominate with things like peace or power, security, or wealth in mind. And in modern international politics strong states have even periodically turned to collective global security management (CGSM) arrangements, somewhat downplaying power balancing.4 This concentrates their power, with that of other states, which allows them to protect themselves and others from threats via their collective retaliatory reactions. A CGSM arrangement is, in part, a general deterrence effort but also capable of immediate deterrence responses via “collective actor deterrence.”5

Deterrence in Practice

A brief overview of deterrence in the 20th century is groundwork for the main subject—deterrence theory in international relations and its prospects. Deterrence is a key component of security management in modern interstate interactions and increasingly in internal conflicts—it is a durable but uneven and controversial resource. After World War II it attracted and disturbed many analysts, political and military leaders, and citizens uneasy about how nuclear warfare might someday eliminate virtually all life on the planet.

By threatening serious harm as a preventative measure, deterrence ideally does little or no harm at all. But it is also used to punish, producing significant death and destruction, when its initial threats lack the desired effect. Deterrence has been intensely studied yet is often considered puzzling and insufficiently understood, and it can be quite dangerous. Its key role after World War II and the arrival of the nuclear age involved the West and the Soviet bloc (the Soviet Union having successfully tested its first nuclear device in 1949) using nuclear weapons stockpiles to put each other (and others) at risk of destruction so as to keep safe, reinforced by lesser threats with less dreadful weapons to curb lesser fighting among themselves or against others. A few other governments soon did the same; their descendants and a few other imitators still do.

Naturally, efforts to understand and explain deterrence were widely undertaken. The results have been somewhat insufficient, though at least nuclear deterrence has never culminated in a nuclear war. To this day, we unevenly grasp and employ deterrence intellectually and in practice, and remain unable to fully displace it. It remains in use despite being a flawed policy instrument, with states living in the presence of potential calamity. Conventional conflict deterrence has only unevenly suppressed non-nuclear warfare—it remains costly, condemned, yet nevertheless continuing.

Since 1949, nuclear weapons have been a dominant factor in modern deterrence and the study of it, confined to a small number of states. The stability of the international system rested primarily on the United States bloc and the USSR and Chinese blocs plus their huge conventional forces, with the leaders working to enlarge their blocs and power. The resulting security arrangement has been successful but expensive, the United States and USSR providing the critical security and stability while paying much of the cost. Tensions between the bloc leaders (and some bloc members) generated expensive and dangerous situations in places like Berlin, Vietnam, Cuba, and Korea involving serious casualties and threats. However, the overall security system remained stable.

From early in the Cold War nuclear weapons and nuclear deterrence have played a major role in “extended deterrence,” which is when a state not only seeks to deter attacks on itself but to prevent attacks on another state or states. Each superpower provided this for its bloc members as well as nonmembers considered important to protect, usually because they were considered important in the context of the Cold War.6

How did this overall deterrence arrangement work? Its theoretical, political, social, and psychological components were roughly as follows:

  1. 1. Each side grasped the importance and danger of nuclear weapons, and thus of conventional weapons which could drag states into nuclear wars nuclear and conventional forces. Therefore they even shared information at times on how to sustain deterrence stability—keep nuclear arsenals safe, prevent accidents and mistakes, and so on—and they carefully handled intensely dangerous situations;

  2. 2. Each was seriously concerned about nuclear proliferation and at least partially tried to prevent it;

  3. 3. Each used extended deterrence to maintain bloc cohesion, reinforcing this via huge nuclear arsenals and conventional forces, and calming fears about first-strike threats and surprise attacks by remaining able to retaliate disasterously—the core component of their relationship;

  4. 4. Each accepted living with those face-to-face military risks;

  5. 5. Their conventional forces periodically participated in violent conflicts as part of sustaining international security—part of extended deterrence;

  6. 6. Each constantly pressured members of its bloc to do more so as to ease the leader’s burdens—with somewhat unsatisfactory results.

    It became clear early on that deterrence could operate via threats to respond by either attacking the opponents directly or by defending against them so vigorously that their plans failed—deterrence by either threating/inflicting punishment or threatening denial of success for their actions. Punishment was attractive if it could readily inflict serious, even crippling, harm; denial could be effective if it sufficiently damaged the opponent by frustrating its attacks. This thinking also affected the leaders’ allies and associates, although different preferences and concerns complicated the nature and conduct of the chosen courses of action.

Another aspect was that the two blocs, especially their leaders, faced threats of MAD (Mutual Assured Destruction) risking virtually complete destruction while trying to deter attacks, particularly a surprise attack. MAD was always controversial because it was meant to make each opponent accept that in another war the result would likely be its total obliteration. The use of MAD prevented a devastating war ultimately by using fear of nuclear weapons to prevent their use.

General and immediate deterrence both applied (and still do in the 21st century). Each side suspected the other would attack given the right opportunity, so both remained prepared, weapons constantly poised, to go to war almost immediately. Deterrence was used to convince a rational, or even irrational, opponent not to attack—to forestall irrationality or at least restrain it, and manipulate the opponent into acting rationally or being so fearful as to do the rational thing in confronting “unacceptable damage.” This obviously required that deterrence threats be at least reasonably credible, which could be difficult;7 but MAD reinforced credibility when perilously near operation.

Success lay in sustaining stability (peace) within any serious conflict. The Cold War was successful this way without grievous harm until it ended in 1990. Immediate deterrence was rarely crucial but quite significant at times (i.e., Cuban Missile Crisis). General deterrence was crucial throughout. And deterrence was often practiced by Cold War participants or other states, successfully and less so, beyond or out on the edge of the Cold War, sometimes by participants concerned about or even seeking possible disruptions of Cold War stability. Thus, this deterrence was a widespread practice with uneven effects that at least forestalled the worst possible harm. However, deterrence below MAD levels of confrontation was less effective in forestalling outright fighting.

As noted earlier, deterrence naturally attracted considerable study and efforts in deterrence theory from early on, and still does, but never with unanimity. Deterrence had its numerous bad moments, generating a litany of complaints about deterrence and deterrence theory in international security studies and elsewhere. This led to calls for more penetrating and empirically enlightening theory. Meanwhile the world remained too threatened, too violent or close to it, and too unstable or nearly so, giving deterrence a somewhat weak reputation.

Here is a brief review of how deterrence and deterrence theory faced serious difficulties during the Cold War and after. It initially offers lessons about deterrence in action, the creation of deterrence theory, and the controversies deterrence inspired. The post–Cold War period began enthusiastically and was initially rewarding but since then has not gone well. Deterrence reemerged as the core of international security management, and that remains unlikely to change in the foreseeable future.

Deterrence in the Nuclear Age

Deterrence theory largely developed out of the necessity to live with a serious East–West conflict (Soviet bloc vs. NATO alliance), with massive conventional forces and arsenals making a serious war likely be catastrophic. Deterrence theory described deterrence situations (indicating what takes place), explained how deterrence works (what determined its outcomes), and prescribed best steps for governments and decision makers.

Deterrence strategy generated plans for using armed forces and nuclear weapons if necessary. It designed appropriate capabilities and planning for conducting war while deterrence theory explored possible arrangements that could be made by both sides to avoid war. Strategy was vital because deterrence threats would not work without the resources for severely punishing the attacker; the appropriate means had to be clearly displayed. If deterrence failed and an attack loomed, a strong attack and defense seemed the only possible means of survival. Complicating things was the idea that the best defense was with a massive preemptive attack—an approach that, obviously, would be provocative. And since the deterrer had to be able to do terrible damage even after being attacked first, so the opponent would be destroyed and thus would not attack. Nuclear weapons were ideal for scaring the other side, destroying it or sustaining a stable relationship, just as long as the wrong steps were not taken by either side.

Deterrence theory handled the serious mistakes problem by asserting that each side had so much at stake it would be only rational to threaten the other with total devastation—or Mutual Assured Destruction—so it was rational for both to avoid war, not start one. That made sense, but of course this approach put each side in mortal danger, which made no sense to observers and was often puzzling to those directly involved.

An important element in early deterrence theory was that a number of analysts turned to rational choice approaches to provide the logic behind all this. Rational choice approaches were already being effectively used to explain and shape many activities (in business, thought, traffic, among others). Analysts thought if rational choice analysis greatly improved such behavior it could greatly improve Cold War behavior, making the parties more effective. Numerous analysts and some officials pursued this line of thinking.

The theory suggested other things needed for effective deterrence. Important on this was the credibility problem in both general and immediate deterrence, which has been complex and annoying for years. Credibility is obviously crucial for effective deterrence, so states, officials, and analysts have given it much attention. Often unreliable, fluctuating, and unpredictable, it is quite important not just against opponents but in relations among allies and associates. This is particularly so in extended deterrence because states, officials, and citizens often dislike depending on other states for national safety, as there is no guarantee deterrers will live up to their promises and meet the risks and costs involved. This fear has often been raised concerning United States extended deterrence in Europe, the Far East, the Middle East, and in the United States as well about it allies and friends.

Deterrence involves issuing threats, but what if the opponent ignores them? The answer: think carefully about what would convince the other side—what statements, promises, and preparations should be made? A deterrer should make its threats as clear and obvious as possible and build a reputation for upholding threats and taking the necessary steps (e.g., moving forces into place). Since nations often cannot trust other countries, issuing a threat must take that into account.

On the related problem of resolve, threats may be dismissed if seen by the challenger as not credible, even though the threat looks dangerous, if the deterrer seems to lack the necessary resolve. Deterrence may then fail unless imposed by some forceful initial action. Resolve is often assessed by challengers based on the opponents’ interests at stake and their relative importance to each party. And resolve may be affected if the deterrer fears for its reputation: perhaps because its threat could put valuable allies at risk, or could be too costly or unpopular with its citizens.

Some analysts were highly critical of rational deterrence theory. For instance, if two states at odds applied rational choice theory via cost-benefit calculations, why would they ever get into a deterrence confrontation? Conflicts must arise from someone’s misperceptions, imperfect information, poor calculations, and the like. Analysts noted how conflicts often spring from misperceptions, mistakes, and other potential threats to deterrence stability. MAD was endorsed partly because misperceptions and mistakes could be far too dangerous and thus states would not take chances.

Governments need information about opponents’ preferences in deterrence situations to handle them correctly, by determining how deterrence will work and why. But that information often seems insufficient, ambiguous, contradictory, or unreliable, in part because leaders shift preferences, delay in deciding on preferences, or grapple with coalitions that shift preferences in making decisions. Thus, advice that deterrence be tailored to the opponent (his history, culture, leaders, domestic politics, etc.) can seem unreliable. And because it is not clear that deterrence works only when the opponent is rational, a successful outcome may not result from deterrence and rationality working together.

Along with these important aspects of immediate deterrence situations, less readily and thoroughly examined was equally important and more broadly employed “general” deterrence. It has had at least three versions: mounted by a single state; operated in an inadvertent version among conflict participants; or as systematic deterrence effort conducted by a concert or a NATO. General deterrence is often present and quite durable. It can be lasting periodically or indefinitely whether mounted by a single state or several. However, the participants must attend to its durability, stability, and internal cohesion on their behalf, and be alert to emerging threats (such as the rise of China) and the emergence of any immediate deterrence situations (e.g., Russia’s seizure of eastern Ukraine). General deterrence remains important. The Cold War was a lengthy display of how this kind of deterrence last very long, and how, even if it dies down, may revive again.

What Went Wrong After So Much Seemed to Be Going Right

Deterrence theory and its theorists had little to say about coping with disappearing conflicts. The Cold War’s sudden end stunned the participants, and it seemed the result would include a sharp reduction in the role, presence, and importance of deterrence in international relations. But officials, states, national and international organizations, and activists were soon unable to handle the resulting developments well. Deterrence lost much of its presence and importance; then made an unwelcome but necessary comeback.

The initial problem was that almost no one was properly prepared to handle things in the abrupt 1989–1990 circumstances—they were too unfamiliar. Cold War collapse came too abruptly, and what replaced it had too little time to evolve. When Mikhail Gorbachev began signaling the Soviet Union would welcome relaxation of the East–West conflict, positive, relaxing responses very rapidly emerged. One shock was how readily this happened politically amid huge piles of nuclear weapons and standard deterrence thinking. East–West relations improved much faster than military forces could readily adjust to. Deterrence as vital resource and recourse shrank even though the possibility of destructive conflict physically remained. It seemed deterrence was convert into more like a component of global security management, and as the situation rapidly improved state deterrence postures quickly faded toward the background. Nuclear weapons and delivery systems, conventional forces stockpiles, and satellite surveillance capabilities still existed but largely more like a remote buffer or backup facilitating the Cold War’s demise. And it soon seemed that a huge military capacity did not a superpower make—the USSR and Soviet bloc disintegrated. Neither side anticipated all this; hardly anyone was prepared for it.

However, the huge retreat from the Cold War and deterrence—in theory and practice—could not suitably design steps fast enough to shape a solidly beneficial outcome for the governments and people involved. The Cold War and deterrence had some underappreciated roots and effects. While they subsided, they were being further shaped in part by underlying national cultures, politics, pride, self-respect, and aspirations of the two sides, along with underlying citizen desires on each side for independent national development efforts (not just bloc memberships) including assertions of their ethnic, religious, and historical identities, and even their past territorial ambitions and entities.

Bloc military and deterrence cohesiveness quickly became more difficult to sustain, particularly in the Soviet bloc. Deterrence began changing not just militarily but by being altered and newly utilized in reacting to shifting developments and factors. For instance, extended deterrence by the more powerful states began to soften or even deteriorate. Significant elements of war materials in the blocs began diffusing. The deterrence that remained and soon reemerged was itself more diffuse, on both sides—in the intentions and objectives of participating states and societies, their reshaping as international actors, and their attitudes on reviving deterrence for common goals.

Aiding this was, initially for the United States, the “Revolution in Military Affairs” emerging from at least three broad scientific and technical developments. First, in surveillance—improvements in detection, observation, and tracking via better satellite reconnaissance, sound monitoring, improved radar and other tracking systems. Second, there was information processing, delivery, and presentation—particularly via rapidly evolving computers and their offspring. The cyber revolution soon began to affect deterrence as well. Third, there was the rising capacity to hit what is detected whenever necessary. All this began shifting and changing many aspects of conflict and warfare, such as the shrinking size of forces, using force with much more precision, and therefore the resulting ability to do more with much smaller forces.

Simultaneous technical modifications in the components of military deterrence were also appearing. Nuclear weapons became more difficult to hide except in advanced submarines and were difficult to track. Planes for delivering weapons began to be less useful until they were made stealthier or more capable of accurately delivering missiles from much greater distances. Missile silos became much more vulnerable to attack, generating calls for their dismantling. Missiles in flight began to look vulnerable to oncoming ballistic missile defense (BMD) developments.

Military conflict also began changing with regard to conventional weapons and forces. Accuracy improvements allowed shifts to less equipment and fewer personnel. Penetration of opponents’ communications greatly improved. Forces became more mobile. Deterrence efforts now had better means of detecting opponents’ improvements and better chances for cheap-victory outcomes in conventional fighting.

“Cross domain deterrence” efforts began emerging, involving new and surprising blends of different capabilities, such as using armed drones for penetration, monitoring and tracking, identification, and destruction in league with ground forces. Deterrence now extends to using costly sanctions, such as those against North Korea, Russia and, until recently, Iran—inflicting punishment without fighting. Deterrence in the 21st century can encompass use of small groups of raiders or machines for sizable reconnaissance, attacks, and disruptions. Technically, some cross- domain deterrence is also now used by terrorists in assassinations; industrial, chemical, and biological attacks; and cyberattacks—expanding their disruption and damage capabilities. Analysts predict cyberattacks will also become more dangerous in the future.

Deterrence is now used not just for threats but increasingly in outright attacks and extended irregular warfare; they are also used against ISIS and related groups that inflict harm and destruction. The meaning of “deterrence” is being stretched from threats of punishment and/or retaliation to applying death and destruction at almost any level in multiple ways and by a greater variety of sources and equipment. Analysts even suggest deterrence can include driving groups of people across borders, seas, or territories to impose serious costs and burdens on a state, or using them as a byproduct in other kinds of attacks. (A good example is the fighting in Syria.) An alternative is to force rapid movements of people, an exodus of some sort, in the area being attacked by using irregular warfare to promote disarray in the state, its forces, economic systems, ethnic and religious groups, etc.

Fighting deterrence is becoming more complex, stretched well beyond its original conception in connection with both nuclear and conventional forces threats. The most significant development may eventually be precision-guided BMD and related weapons, undercutting current nuclear and conventional missiles. (The United States is hard at work on this, irritating Russia and disturbing China.) BMD may end up eliminating or greatly reducing fears of preemptive strikes and the value of nuclear and other missiles, perhaps allowing nuclear weapons states to adopt more relaxed relations. Alternative developments might involve secret nuclear weapons for smuggling, close-in submarine attacks, ever more stealthy aerial attacks, and the like; or tougher collective efforts to prevent nuclear proliferation and reduce nuclear threats (as after the Cold War), with similar efforts in non-nuclear military capabilities.

Extended Deterrence

Extended deterrence remains important, even crucial, in places, with a central role. It still involves a state using deterrence threats to protect another state or group. Signaling that attacks on friends will be punished includes steps such as announcing the threat; maintaining forces in or near the protected party; sharing military plans, equipment, and training; and providing weapons and regular defense consultations. It can be a long-term, intermittent, or short-term security collaboration. The parties may have a formal alliance treaty, normally covering more than deterrence, or settle for an announced attachment. The most prominent example is the 27 members of NATO, under what is primarily US extended deterrence, assisted by other states’ more modest contributions.

What initially made extended deterrence significant was the United States and Soviet Union provided nuclear and non-nuclear deterrence to Warsaw Pact and NATO members, including protection even from domestic forces attacks or uprisings. Numerous states in Europe, Asia, and part of the Middle East became beneficiaries, often housing American or Soviet conventional forces and sometimes their nuclear weapons. Some 160 to 200 US nuclear weapons are still stored in Europe today (much fewer than before), but those in Japan and South Korea were returned from Okinawa in 1972 and the ROK in 1991. Surveys in the ROK find many South Koreans would support the return of US nuclear weapons to offset North Korea’s (some 10 to 20), while others favor the ROK developing its own.

Extended deterrence remains complicated. Invariably, some citizens want the deterrence provider’s nuclear weapons or conventional forces removed. Accidents or misbehavior by the foreign forces promote disagreements between the protector and the beneficiary. Russians and Americans (and others) are often disappointed by their respective allies’ failures to provide enough economic, military, and political support, which the allies always say they cannot afford.8 The respective allies of the United States or Russia may not deliver protection if the need arises, particularly if it involves using nuclear weapons.

There are regular disagreements among the participants over interactions with opponents; Seoul collaborates with China on too many matters to suit the United States, while Romania and Hungary get along too well with Russia. Israel chides the United States for being too kind to Iran. The parties quarrel over priorities or strategies. States near Russia often press harder than others for improving East–West relations. The ROK resisted American pressure for years, until 2017, to install US THAAD antiballistic missiles to appease China’s objections. European allies have resisted, or only half-heartedly participated in, US military operations for many years in the Middle East—their priorities have been closer to home. Thus, allies or associates often lack consistently strong attachments, or clear agreements, on how best to get along with formidable opponents.

Allies are also often averse to using force; this has been true of various European countries. New Zealand and Japan are averse to major military activities, maintaining large forces, having heavily armed military personnel, and preparing for major fighting. Japan relies on US protection, and its constitution does not allow direct participation in major military conflicts. This is unusual for a potential major power, but the Japanese know if they abandon that posture then China, Russia, and the two Koreas will take umbrage.

Thus extended deterrence is odd—odd that so many states rely on it, that the United States has expanded it so much (and at such great cost), and that it can make for such tangled geopolitical relationships. Yet it remains vital in stabilizing global and regional security, curbing or preventing many conflicts, restricting nuclear and some conventional forces expansions, and inhibiting some nuclear proliferation deals. At the nuclear level it remains unlikely to be militarily activated (a possible exception is the North Korea situation). Despite its success it remains difficult to sustain deterrence cooperation.

The State of Deterrence Today

When the Cold War ended in so far as nuclear weapons and nuclear deterrence was concerned, the new post–Cold War era did not discourage expanded cooperation among the participants because deterrence did not replace the primacy of politics. Instead, alongside intense pressure from domestic political forces for serious detente, deterrence provided useful security for covering the retreat from the Cold War during the initial discussions and concessions in relaxing hostilities and adopting major cuts in forces. The result was a burst of cooperation and interaction in 1989–1991 (somewhat offset by fighting in the Balkans as Yugoslavia disintegrated). The enthusiasm, particularly for global security management, seemed likely to bolster and expand deterrence efforts by the UN, NATO, the European Union, and other regional bodies. It encouraged greater efforts to end nuclear proliferation, suppress war crimes, and curb human rights violations. It included repression of internal fighting such as by terrorist groups and organizations in Africa and the Middle East, which were often heavily armed and intent on attacking people, societies, and institutions, often causing destruction of homes, churches, buildings, even whole villages and towns.

At the dawn of the 21st century, shifting attitudes and behavior began producing a significantly different deterrence environment. In many parts of the non-Western world political figures, groups, and other elements have worked to offset or avoid the West’s impact, seeking to avoid the dominance of things Western. There is still Western military intervention in various countries, sometimes for extended periods, and still present in some places to tackle deplorable human rights situations. Substantial Western influence often met with rejection from religious, tribal, cultural, or other elements, and from political elites or dictatorial regimes maneuvering to retain power and national wealth in Africa and parts of Asia. In the Middle East political and social unrest is initiated by dissatisfied ethnic groups, plus sizable and well-organized terrorist groups driven by disgust with ineffective, often repressive regimes, by religion, and by anti-Western cultural beliefs attached to a willingness to die.

In other cases, that rejection drew on deeply rooted national political elements—particularly in China and Russia where Communist Party leaders or former leaders, and like-minded rulers elsewhere mounted campaigns to shrink contact with the West and Western culture, attacking it for seeking to deliberately undermine their countries, cultures, and economies. This includes rebuilding Cold War antagonism around old assertions of being at war with the West. The Kremlin talks this way, so does North Korea—with better justification—and even more energetically. And China continues tightening controls over citizens, the party, and interactions with the West, particularly the United States. Included are nuclear and conventional military buildups and upgrades, revived efforts to seize border areas as cushions, claims over large ocean sectors, and steps to resist Western presence in neighboring areas to avoid (nonexistent) planned attacks by Western governments. The real fear is that association with the West will undermine the regimes, their authoritarian rule, and political control—thus justifying the need to rebuild deterrence and expand their military capabilities. In the Middle East political and social unrest has attracted Western attention largely in part because, directly or via threats, the situation drives people to flee to the West, creating major immigration problems and burdens. Coupled with deterioration of Western domestic, intellectual, and academic support for using threats and force at the global, state, and intrastate levels, this has resulted in a deterrence retreat of great current and prospective importance.

All this arose within an international environment that had started to generate great expectations. With no Cold War and a sharp decline in Great Power conflict, most of the world’s nuclear weapons were eliminated.9 Nuclear and other deterrence resources were recessed and reduced. Major powers’ weapons systems, production facilities, and military stockpiles shrank markedly—physically, in political-strategic terms—in readiness and perceived utility for war in deterrence postures and in public acceptance.10 The nuclear weapons, especially the arsenals, became obsolete, at least temporarily. The growth rate in new or potential nuclear powers sharply declined.

But soon, however, nuclear deterrence and its components gradually revived. The United States, Russia, China, North Korea, India, Israel, and Pakistan began modernizing and/or expanding nuclear forces and thus inviting arms-race revivals. Justified as healthy deterrence steps and offsetting competition, the aforementioned countries are actually eroding the earlier deterrence contributions to minimizing the nuclear weapons threat, reflecting declining relations among some nuclear armed states and strains in their relations with others. Whereas most nuclear armed states significantly cut their conventional forces after the Cold War, they rely more now on nuclear weapons in the emergent security environment.

At the regional level, deterrence decline has largely lost ground. Examples include the tension and fighting in Ukraine and resulting Western sanctions against Russia; Russia’s threats over the status of Russians in Eastern Europe and its military demonstrations around the Black and Mediterranean seas; and the tightening of current and planned NATO force postures in response. Dangerous situations exist in North Africa, the Middle East, and Afghanistan—there is fighting in and among states, nonstate actors with state support, with limited outside military interventions and financial support from various states. Deterrence has had limited success as it relates to numerous local, regional, and global-level actors. The results? Huge refugee flows, rampant terrorism, Great Power failures to mount sufficient threats and deter successfully, constant casualties and destruction, plus limited great power cooperation at the global level amid parallel breakdowns in regional security management. Internal fighting in Pakistan and Afghanistan continues, which means ethnic, religious, terrorist, and political conflict. China is at odds with many neighbors due to its military buildup and claims to surrounding areas, not to mention its increasingly tense relations with the United States. Africa is rife with military conflicts between and within countries. In Southeast Asia fighting continues in and along the borders of several countries. All these deterrence efforts have generally failed, whether mounted by local governments or outside states and collective actors.

Deterrence at the state-to-state level and below is now a more volatile endeavor and necessity. The need is substantial in and among some states, leading governments, and international organizations, but is not going well. Their efforts may even be making things worse. Various factors continue generating large weapons flows among and within states and to insurgents, international and domestic radicals, and organized terrorists. The impact on deterrence gets less attention, so it is becoming more difficult to maintain domestic peace and security in many places even with outside military support. Deterrence is becoming still more combat-oriented, but deterrence threats look weaker when arms and other military capabilities are plentiful, and the spectrum of military threats is broader. The threats have become more difficult to deflect or stamp out. Many fighters are driven by motivations that ultimately disregard casualties—they fade from sight when vigorously confronted, returning when attention shifts elsewhere but are always ready to accept casualties. While state-to-state wars remain scarce, thanks partly to deterrence responses, these other threats and violent conflicts show little regard for standard deterrence threats and applications, even when delivered by special operations units and well-trained regular forces.11


The overall situation is partly due to (and partly responsible for) the West’s retreat from Collective Global Security Management (CGSM). After 1990 the United States and others led interventions to promote and sustain peace and security by shifting the focus toward a new CGSM arrangement, orchestrated in the Bush and Clinton administrations along with European allies, applied in the Balkans, Iraq, Afghanistan, and the Arab Spring. (The UN and regional associations had little impact—the UN shunted aside by the United States in the Iraq War.) Eventually a new arrangement involved NATO and US alliances or arrangements with a number of other governments, the goal being to provide general deterrence and CGSM to stabilize security in troubled places, and immediate deterrence when war loomed or had broken out. Included was readiness to provide deterrence for societies with brutal or weak governments barely managing divided societies and experiencing violent conflicts or threats. This expanded traditional deterrence into nation building, humanitarian activities, government support, suppression of terrorists and other anti-Western elements, suppression of other domestic violence, upgrading police and military forces, and modernization via military and non-military deterrence efforts.

The justification has been that factors such as internal disarray, violence, humanitarian disaster, and serious human rights violations are conditions that readily generate threatening situations within and across national boundaries, particularly in a shrinking world. After 9/11 the main focus was also on terrorism, culminating in wars in Iraq and Afghanistan (not to mention interventions elsewhere) that have never fully ended. Except for terrorism threats, American deterrence and related endeavors by others (mainly Western) were at least partly disengaging from direct threats to the United States and its allies and redirected toward deterrence aid in other governments, societies, and regions. Justified primarily by humanitarian concerns, threats to US interests, fears of spreading disarray in various places, and the protection of allies, it represented hopes of spreading liberal democratic ideas and practices. All this came with utilizing and maintaining a network of bases, training for overseas government and military forces, stockpiling arms abroad, providing arms donations and sales, and using special operations and private security forces. Expanding the concept and use of deterrence, many targets were not threats and sometimes not even military in nature. Deterrence had become more like deterrence by denial but inflicting harm through a broader spectrum of goals. Working with local forces or those supplied by friends and allies took on aspects of collective actor deterrence. Thus, it became more complex, multifaceted, and multilayered, involved in fighting but also associated with things such as community development or humanitarian activities for backup support.

As a primarily American effort and preoccupation, with varied support and involvement by others, friends and allies have sometimes felt they joined American conflicts for American objectives that had few attractions. When the efforts went badly, the United States shifted to more selective intervention—as in its response to the Arab Spring. One result is circulating conclusions that the United States is getting weaker, less capable of leading the world’s dominant coalition, and less committed to protecting allies. US deterrence credibility suffered. Support in the United States and other Western states for global security management efforts lost significant backing due to limited success, high costs, casualties, and tendencies for those being helped objecting anyway. Amid the Great Recession’s impact on morale, government budgets, and national priorities, the scale of American intervention shrank.

Many states that relied for years on US deterrence cut their defense budgets sharply. NATO European budgets collectively sank to half or less of US defense spending, even with expanded NATO membership. Only recently has Japan moved toward pursuing a more suitable Great Power military capability and considering more participation in global security management. South Korea, with substantial forces, still relies on US ground, air, and missile defense efforts, naval forces, and advanced targeting and tracking. The CGSM steadily declined in support until the deterioration in West—Russia relations led members to start military mobilization efforts again, albeit slowly. Deterrence has become more complicated, needing adjustments due to greater uncertainly about how global security must be managed. Related is increased interest in deterrence by denial, anticipating that if Western deterrence threats lose credibility defeating opponents will be increasingly required to defeat them.12 But NATO is flailing about on this.

Shrinking CGSM is the most significant deterrence development of note. The outcome will eventually be the resurgence of power balancing; its components are already apparent in Russian and Chinese military spending and defense expansion, plus their preoccupation with controlling buffer and border areas. Many analysts now champion power balancing as the best route to peace and security; others regard it as inevitable. It works unevenly, but this is how states will behave eventually. They call for reduced US (and Western) security managing and cuts in in deterrence activities; this is because the supposed US national interest in global peace and security is overblown. Some analysts dismiss the Russian land grabs in Crimea and eastern Ukraine, saying the West has no serious security interests there and that Russia has naturally resisted Western efforts to absorb Ukraine. One could argue that a major state would naturally want to protect its border and regional interests—and thus the current clash with Russia is really the West’s fault. This stimulates calls for sharply reducing deterrence efforts at the state level; as for stabilizing regional security systems, we must leave that to power balancing.

Additional Results

Military materials have flooded the world in recent decades, especially from the United States.13 Many of these relatively modern weapons have been going to military depots, rebels, criminals, leaders of clans, tribes, and religious-ethnic groups, among others. Many recipients have serious military training from interaction with Western forces. Deterrence threats are therefore less effective, and deterrence interventions confront opponents with much better capabilities and resources, making interventions more costly and dangerous. Another result is weakened governments such as Iraq’s, due to violent domestic challenges from new or revitalized groups (some cross-national) representing religious, ethnic, and other grievances and aspirations. ISIS is a major example of a group being so well equipped for exploiting violence. Unfortunately, escalated moral restraints promoted with regard to confronting those conflicts—inflict fewer casualties, damage less property—grant amoral opponents greater leeway for more harmful behavior.14

As noted earlier, wars in Iraq, Afghanistan, and elsewhere left much military equipment behind. Considered too expensive to ship home, this equipment has been given away, stolen, lost, sold off cheaply, seized by enemy forces, or turned over to them by local officials. Continued elevations in modern technology reinforce violent efforts by terrorists, ethnic or religious groups, and other factions. This has greatly improved the military capacities of groups the West wants suppressed, directly or by strengthening local governments and favored groups, greatly improving difficulties in sustaining or reviving peace and security in the Middle East, Africa, and elsewhere. Target groups are more willing to ignore or actively confront deterrence efforts, having acquired good equipment, more mobility and better firepower, and modern communications.

New threats to peace and security at all levels of the international system, plus declining capabilities for confronting them, have meant weaker deterrence efforts, often less well supported and sustained over time as conflicts drag on. Efforts to reverse this have been hampered by lack of consensus and slow gains in resources, encouraging the appearance of serious conflicts in several places almost simultaneously, especially during the Arab Spring. Those developments have had serious ramifications (in energy, refugees, terrorists and terrorism, suppression of liberal values and practices, collapse of some governments, a surge of anti-Western sentiments). With interest in decline, immediate deterrence responses to deteriorating situations have been weak or delayed, fighting often breaking out and spreading before efforts to control it are seriously discussed.

Stretching deterrence for use against nonmilitary threats or threats well short of war, for dealing with small armed units or individual terrorists, criminal groups, and assassinations and also expanding uses of deterrence to deal with cyberattacks, back severe sanctions, provide military training, and make selective raids—this approach is new and challenging. And deterrence is sometimes now extended to cope with large cross-border movements fleeing internal conflicts, genocidal hatreds, breakdowns of domestic order, and regime collapses.

Things to Keep in Mind About Deterrence Theory

Deterrence came to prominence and remained so largely because of the threat nuclear weapons posed, reinforced by the Cold War. After that, as relations among Great Powers eased and nuclear arsenals shrank, the assistance provided by deterrence theory naturally received much less attention. One discussion on expectations of future continued interstate competition in East Asian international affairs listed various scholars’ theories: Robert Gilpin (system governance thesis); A.F.K. Organski and Jacek Kugler (power transition thesis); Kenneth Waltz (balance of power theory); Stephen Walt (balance of threat theory); Robert Jervis (security dilemma theory); Michael Doyle (democratic peace thesis); various analysts (Neoliberal institutionalism). All suggested, for instance, a rising China would be disruptive in international politics and would challenge US dominance. None focused intently on deterrence.

This is now changing again—and fairly rapidly. Deterrence remains heavily affected by technological change and the interaction of security institutions with civilian-generated technical advances—the “cross-domain deterrence” approach, for example.15 This is prompting a rethinking of deterrence, with numerous implications for its future via aspects of it now evident in, for example, designs for future American forces to enhance aspects such as stealth, flexibility, capabilities, speed, weapons effects, and expanded use of cyber technology.

For instance, Russia is producing large missiles with small warheads to adapt to conventional weapons use and is developing ways of releasing clouds of radioactive contamination near major cities. The United States and China are exploring the development of hypersonic glide vehicles tearing back into the atmosphere after flying into space maneuvering to avoid missile defenses—the Chinese version carrying a nuclear weapon, the US version designed to be smaller, stealthier, and more precise so as to hit targets with destructive precision, via entry at an extreme speed and without needing a nuclear detonation. Russia and China are seeking to develop space weapons to attack US satellites that would guide American weapons at the start of a nuclear war. Technological changes are threatening to seriously disrupt the strategic stability that has long been associated with deterrence. Improvements in accuracy and lethality are expanding the effectiveness of conventional weapons for attacking nuclear weapons. Huge improvements in sensing from space are improving detection of targets, which can readily turn intended retaliatory capabilities into readily eliminated weapons instead. And efforts are well underway to make counterforce resources (from planes, ships, and submarines, for example) more mobile as a result. All this could sharply erode strategic deterrence stability.

Next, is the growing problem of deterrence durability when used at any magnitude, at least by the West. Public support in democratic societies readily erodes from casualties and costs involved in military deterrence steps, especially if deterrence is frequently called for, and the workload is quite unevenly distributed among allies. Support also erodes because of humanitarian considerations; civilian casualties, plus destruction in civilian areas, can rapidly generate complaints from citizens, allies, friends, international organizations and groups, particularly in the West where deterrence is broadly entwined with moral concerns. With use of nuclear weapons always treated as a distant possibility, now the present situation similarly affects and curbs use of many conventional weapons and inflicting civilian casualties. This is not universal but a predominately Western problem, unlike shifts in Russian deterrence thinking toward merging the use of nuclear and conventional weapons.16 However it may spread eventually; interest in such steps is rising.

Another consideration: threatening is easy, communicating threats accurately and effectively is difficult. Standard miscommunication is obvious, but there are also the effects of perceptual and cultural barriers as well as emotional reactions. Threats are often treated as insulting, abusive, or demeaning: this rigidifies the opponent’s thinking on plans to attack, among other things. Nationalist, ethic, religious, and related loyalties readily drive conflicts and shape rejections of deterrence threats, and other loyalties can readily be more profoundly felt than conflicts themselves. Causes at stake are often taken as more important than life—behavior currently on display in the Middle East—and often erase the expected responses to deterrence efforts.

Finally, the most serious problem in the nuclear age—the possible escalation of war to an extreme level—now has serious parallels regularly turning up well below the nuclear level. Thus the standard concern about a North–South war in Korea is that it would bring Chinese military intervention and the involvement of the American forces already there, with other neighbors perhaps intervening to prevent waves of refugees at their borders or seacoasts. Syria is a good example now. Fears of confrontation or military strife, between Russia and the West are becoming more substantial as both pursue military buildups again. Confidence that deterrence prevents attacks has slipped; recent Russian and Chinese behavior indicates they consider American deterrence less credible, as do various American allies.

Contemporary Deterrence

Can deterrence theory be made more empirical, coherent, accurate, and broadly or universally applicable? Here is a disparaging view:

The history of the theory and practice of deterrence makes a strong case for concluding that while certain abstract elements of deterrence have something of a universal character, the degree and nature of its challenges and implementation are so uneven and varied, the operational conceptions of deterrence and the specifics of both challenge and response are so elaborate, that it is inevitably lodged in the varying national and political character of conflicts, shaped by the social and cultural details of the motivations, perceptions and analyses that drive challenges and responses. That is a long way of saying that deterrence, in crucial ways, is not sufficiently consistent to be fully captured by our theoretical apparatus and empirical studies.

In many ways this continues to apply.

How might an effort to enhance deterrence theory best proceed? To start with, the objective should be to tackle deterrence in both theory and practice. As for practice, deterrence is now working unevenly in numerous places, even inside several states contending with civil war of some sort. It is seriously strained in states such as Pakistan, Afghanistan, Mexico, Libya, Iraq, and others. Various explanations of this need exploration.

First is the question of whether deterrence on the global, regional, state, and local/domestic levels is the same basic phenomenon (i.e., threats of harm drawing official threats of deterrence by punishment or denial, and with crude deterrence often practiced by nonstate elements within and across state borders regionally or even globally by ISIS, cyberattack entities, and other transnational attacker entities. Exploration of contemporary deterrence by level would be a good start.

Next, it is important to examine whether, in the current international system, strains on deterrence effectiveness are essentially due to international organizations, governments, officials, and citizens becoming tired of trying to make it work effectively. One approach would be to examine cases of lengthy deterrence operations against the same opponents—the long struggles against rebels in Colombia, Afghanistan, or Syria, for instance. The question for such studies would be whether extended deterrence efforts are, in various kinds of studies, not much different from deterrence cases conducted in short (or at least much shorter) fashion, or whether such cases turn out to be typically quite different from others.

Since deterrence efforts vary greatly in length and intensity of effort, it is necessary to explore variation in success—such as success achieved versus the original degree and nature of success sought and how and how deeply satisfactory the success is seen by the deterrer. The same is true for challengers—how much variation in success or failure is there and how much dissatisfaction. Next, it is necessary to assess how often success and failure occur: to what degree and with what impact. This is a complex task given the great variety in deterrence cases and the ambiguity that often emerges about how they ultimately conclude. Alternatively, a good question is whether failures were (or are) due to deterrer exhaustion—when IOs, governments, officials, or citizens tire of wrestling with failures or inadequate results. Many developments can shape outcomes: breakdowns in security crippling deterrer efforts, rising costs and casualties, recession and slow recovery, parallel violent conflicts or disorder emerging in multiple places, accumulation of additional problems and burdens, and so on.

Strains on deterrence readily arise from an endless array of possibilities: negative reactions from people meant to be helped, insufficient interest in and responses to Western (or, say, Russian), social, economic, and political penetration; or their superior capabilities and activities; or significant cultural differences often uncomfortable in deterrence-relevant locations; or non-deterrence-related interactions that nevertheless irritate. A foreign military personnel presence can be seriously irritating or threatening without intending to be, particularly when opposition coalesces and mobilizes.

Explaining strain on a deterrence effort, at multiple levels, requires appreciating its evolution and particular conduct of operation, especially if personnel from numerous countries are involved and insert an array of behaviors, activities, and sensitivities from their societies. Modern deterrence efforts often include immersion in more than controlling threats (i.e., providing health and medical efforts, resources and applications, recovery and repair work, temporary employment for locals, and so on). Such activities may do many things, yet could also put the populace in harm’s way when the targeted opponents disrupt those interactions or condemn the locals for participating via fighting, kidnapping, or destruction of villages and towns.

In short, deterrence has changed a good deal in the last thirty years and is still changing. Deterrence theory did not predict nor explain the collapse of the Cold War, the sharp drop in some deterrence matters, and the resurgence of deterrence again. The activities involved now widely vary in impact generating numerous sorts of feelings well down into societies where deterrence success or failure can be considerably tangled. It has come a long way from simply fielding a military threat, punishment, or denial.

To continue developing a better grasp of the nature of deterrence and its effects calls for entering into more specific explanation and application of these elements:

  • ranking deterrence components in order of probable relevance and importance in the situation at hand, based on empirical evidence

  • ranking deterrence-in-practice details in order of probable specific utility and how best to study them and their practical roles to suit the changing environment

  • assessing resulting studies in accuracy and how best to design and apply them in the future

  • reorganizing and reordering thinking about deterrence in action from the ground up, to diminish practices that produce too many unwanted outcomes

On Contemporary Deterrence Theory

Is the best way to proceed upgrading the fundamental components of deterrence theory via a thorough review? Is an entire reexamination needed of what is supposedly known to encompass the changes in deterrence and adjust it appropriately? Or proceed by tackling portions of theory that apparently most need reexamination? Is deterrence theory significantly out of date, or just in need of careful analysis and revision? Is the best approach a thorough review of the necessary reviewing?

An initial necessary step is confirming how deterrence is experiencing major shifts and is somewhat rebounding from having to alter its components via, first, a surge away from conflicts into cooperative relations followed by coping with altered deterrence in a new environment. The next step would be toward again containing conflict and attacks with serious opponents. Adjustments to theory must involve weighing how the changes will likely end up and with what results. A suitable question to further explore is how and why a profound conflict such as the Cold War ended and why that achievement so quickly began to come undone—what caused the huge breakthrough, and why did it go wrong? Was it a gamble in taking an abnormal and ultimately unsustainable chance?

And is it best, therefore, to search for a new clustering, tracking, and ranking of deterrence theory elements alongside its familiar sections, aspects, and flaws, so as to better conduct deterrence and deterrence theory in the changing international security system? Or will it be best to entirely rethink deterrence for keeping up with continuing system changes and reshaping its position in domestic and international environments? “Perhaps most promising would be exploring how deterrence must look into and operate in our evolving international system’s, and its subsystems, security situations—trying to predict, assess, and ultimately apply deterrence and deterrence theory effectively in strenuously trying to get ahead of those developments enough to do better in helping shape them.”

A major concern must be: is there a suitable empirical base? And what are the most promising theoretical perspectives to explore? Is there a basic conception of the current and prospective direction of international security development and change that can properly drive the direction of our predictions, studies, and analyses in shaping deterrence theory? Can all this be ranked in priority in terms of the four levels? What must always be kept in mind is why we continue to lack a clear, sharp theory widely accepted by analysts and widely used by practitioners—with often beneficial results.

Here are various potentially correct explanations that somewhat reflect and fit in the evolution and study of deterrence now. First, with regard to deterrence international and national organizations, states, and groups are not consistently rational. Thus, political and military leaders often disagree about deterrence efforts. Relevant actors interpret their deterrence environment fairly frequently but often incorrectly. They often disagree on what is rational from the perspective of their place in their own system; they also have disagreements over what behavior, in terms of rationality, to expect from state and from lower level antagonists (even allies’ and friends). Conceptions of rational courses of action are inconsistently rewarding, partly because competing interests, ideas, and objectives must be successfully (although not fully rationally) blended.

One major problem is that deterrence involves hard thinking and action that often must be kept at least partially secret. Many of its aspects and actions can be explicit, but a good many cannot, which is often unhelpful. The degree and scale of secrecy typically varies considerably among participants, and so does the scope of available information and resulting behavior. This handicaps development and conduct of policies and actions. This states, statesmen, other officials, and supporters often misread what foreign friends and foes will perceive, think, and decide in decisions involving deterrence in conflict situations, especially when it comes to their long-term deterrence behavior.

Second, leaders and other decision makers weigh steps in conducting deterrence activities that pertain to important, and unimportant, issues and events. This can be quite complicated and thus mishandled, which is to be expected. The most serious problem in deterrence may be that decision makers often insufficiently anticipate this and thus carefully plan for some alternative courses of action if things go badly.

Third, much potentially valuable information about opponents may not be available—as they are committed to secrecy also. In addition, high-level officials may be shrouded from not only what foreign officials think but even what people in their own government think. This can hamper effectively assessing the credibility of foreign governments, leaders, other officials, and even detected spies. This can also affect not only how opponents see themselves and those adversaries they are facing but also how opponents assess their own (and foreign actors’) past and potential behavior.

Fourth, given somewhat uneven, and unevenly available, information, parties often misread situations. This well-known problem is often depicted as the “fog of war” or happenstance in which decisions were made and actions taken.

Fifth, deterrers and opponents may well be short on experience in deterrence, new to the deterrence situation at hand, and unprepared for its intensity. Too often the degree of this intensity can be unknown or incorrectly expected.

Sixth, domestic factors that impact involvements in international politics can vary widely, probably often. For example, the main Republic of Korea political parties see the North Korean problem, the THAAD missile installation effort, the ROK relationship to China, and the ROK relationship to Japan quite differently. This often affects decisions and helps drive policy vis-à-vis North Korea. In another case, there was divided opinion in Britain on whether to withdraw from the European Union. In each case, high officials’ expectations of the government and the citizens has varied widely.

Domestic thinking about foreign policy in general can be quite varied, and so can thinking on past wars and other military activities—the costs and losses involved, the value of the allies, the outcomes, among other factors. Thus intense feelings about Japan’s conduct during World War II remain highly salient in the ROK and a significant issue for many of its neighbors. Japan’s feelings about World War II also remain strong17, and these feelings are still limiting Japanese military efforts. Russian feelings about losing various republics when the Cold War ended are passionate and therefore strongly shape and support the Putin regime’s behavior. The Chinese retain an intense opposition to Taiwan’s independence since World War II as well as the continuing US support of Taiwan which contains Beijing’s behavior on that situation. Domestic thinking can readily affect states’ priorities on military versus domestic concerns, or on expansion abroad versus domestic needs. NATO citizens vary significantly about these matters, generating much concern about NATO’s future durability. For example, on deterrence there is considerable disagreement in Western Europe about bearing the costs of confronting Russian threats, on how committed the United States will remain to NATO, on members’ national interests and how these relate to Russia in general. On refugees from the Muslim world there are widespread differences across Western Europe.

To illustrate the complexity often found in deterrence efforts, here is a short example. North Korea has long been troublesome for China, the ROK, the United States, Japan, and Russia. China and Russia once had relatively normal relations with North Korea, whereas the US and the ROK did not. Since 2000 North Korea (DPRK) has become more threatening to the ROK via limited but harmful attacks and a nuclear weapons program. It has seriously alienated China. Most importantly, it has developed nuclear weapons and tested numerous missiles for delivering them. The other states strongly object and want the nuclear weapons program halted and dismantled. The UN has condemned North Korea for human rights violations and developing nuclear weapons. And the UN has also repeatedly levied serious sanctions on North Korea, which are supported by the states that surround North Korea and particularly by the United States. Those states are unsuccessfully practicing deterrence. Why?

North Korea intensely fears the United States and wants to destroy it—hence the 10 or so nuclear devices produced thus far and the plans to eventually develop nuclear missiles that could threaten parts of the United States. The ROK and North Korea are heavily armed; their huge forces face each other on high alert along the border. The ROK wants Korea unified under its rule, which the United States strongly supports—having already been entangled in the Korean War. The Korean peninsula and surrounding area depends, for continued avoidance of outright fighting, on long-standing American extended nuclear and conventional deterrence for the ROK and Japan. So does overall political-military stability in the northeast Asian region.

China insists North Korea survive, having fought the Korean War to create it, so it strongly opposes Korean unification, so it officially upholds current sanctions on the North but actually lets many banned materials get into North Korea anyway. It fears the US-ROK alliance will continue and US forces in the ROK will remain (perhaps someday even move to a unified Korea’s border with China), posing a serious military threat to China. Meanwhile the ROK flirts with the idea of developing nuclear weapons itself or obtaining some from the United States, although the United States flatly opposes this idea. Japan strongly dislikes being within range of ever-proliferating North Korean nuclear weapons, knowing North Korea’s strong anti-Japanese attitudes, and has carefully laid the groundwork for rapid development of nuclear weapons if necessary.

South Korea plans to install US THAAD anti-ballistic missiles to thwart North Korea, while China condemns this, claiming the missile system will threaten China’s nuclear missiles, a crucial component of its deterrence capabilities. So Beijing says the missiles will seriously damage China-ROK relations. (The United States leads in development and production of anti-ballistic missiles.) Russia is not comfortable with being of minor importance in these matters while likely to also be endangered by ROK nuclear weapons. Japanese nuclear weapons programs were developed to offset North and South Korean nuclear weapons, and the continued US military presence in and around Korea has always involved nuclear weapons on US submarines and bombers.

Northeast Asia fears the United States may soon decide not to protect South Korea because the ROK has much stronger conventional forces than the North and because many South Koreans complain about the US-ROK alliance and US soldiers stationed in Korea since 1945. The United States is also irritated that South Koreans suspect it will renege on its extended deterrence if they are attacked. It complains that the ROK and Japan do not spend enough on national defense, leaving much of the burden of defense on the United States. Japan and South Korea regularly clash with China over its claims to the East Sea and numerous islands; this has led to face-offs, a growing ROK navy, and a Japanese navy that already disturbs China, South Korea, North Korea, and Russia. Meanwhile, a dangerous situation festers. North Korean ruler, Kim Jong Un, is considered very dangerous, a risk taker, and determined to make North Korea a fully nuclear-armed state and remains exceedingly difficult to deter from continuing with his plan.

This exemplifies the sorts of difficulties deterrence efforts faced by many states. Of course, states may stumble, explaining why and how deterrence is often somewhat unsatisfactory and how cooperative deterrence efforts can be extremely complicated, difficult, and unsatisfactory even when deterrence has been sustained and at least sufficiently effective under considerable strain. It shows how states involved often cannot be fully satisfied, cannot make deterrence work to their satisfaction, cannot fully understand or be comfortable with each other, and how relying on a great power to maintain security and order can also seem threatening and suspect and why it might readily discard its deterrence commitments and go home. It is a fine example of why developing a suitable, effective theory of deterrence is difficult and elusive, thus providing a somewhat shaky basis on which strategy must be designed and applied.

Other Directions to Consider

Global security management is unavoidably crucial as international affairs steadily become increasingly interrelated. The context for deterrence therefore grows ever more complex as the development, or deterioration, of deterrence proceeds. That context contains at least two significant components underappreciated in the modern history of deterrence. One is how profoundly deterrence is shaped by politics, international and domestic. The improvement of deterrence theory and the design and application of deterrence as a strategy are partially but importantly rooted in domestic political systems (with varying orientations, fears, and ambitions toward the outside world); they are also dependent on the resources and objectives of those systems and their respective supporting and facilitating political basis. Behind external deterrence efforts are some sort of internal structures and domestic weight. This requires constant attention at the four levels and in their interaction, as political activity helps contain, shape, drive, and implement the issues and objectives, institutions, norms and practices, and treatment of citizens as well as political, religious, ethnic, and other groups. The domestic impact is an important factor in deterrence

The second component is management: economic management on multiple levels; environmental management rapidly expanding out of necessity, science and technology management that steadily enlarges and alters the variability and depth of international cooperation and conflict, and developments in population management that are unavoidably sensitive and problematic. All will help constitute and shape the environment for deterrence and its continuing development.

Collective security management remains disturbingly problematic, largely because numerous countries dislike the West’s management practices, despite these practices often being beneficial. Governments and leaders draw on that dislike to try and negotiate this management’s future development and operation. Thus, they will continue sensationalizing the West’s supposedly detrimental contributions, harassing its managers, and expanding and exploiting distaste for the West for nationalist, economic, political, electoral, and other reasons. And Western countries, reacting to others’ criticisms and behavior, will continue to be dissatisfied with their own management efforts—citing the excessive costs, lost time and resources, limited results, and excessively self-centered decision making constantly present in many states. The West will retain its share of preoccupations for nationalist, economic, political, electoral, and ambitious reasons as well. Deterrence under these circumstances will be applied and often warped accordingly—in the midst of conflicts, political unrest, shifting societies, and military developments and complications.


Contemporary deterrence is becoming more complicated and dangerous, seemingly less effective, which will continue for some time to come. Under current trends, the application of deterrence will continue fragmenting. This will reflect the increasing complexity of states, societies, and their interactions (friendly and adversarial). Collective Great Power deterrence efforts for security management are not ready to be intensively mounted again, and states’ relationships lack the depth of a true balance of power system to provide reliable alternative assistance when necessary. But relations between the United States and both China and Russia strongly suggest a traditional balance of power system may reappear, giving the international system a more traditional security structure. Recessed nuclear deterrence may resume declining alongside the return of more reliance on conventional deterrence threats for global and lower level security, even as system management at regional, state, and domestic levels continues to be somewhat chaotic. In plain sight are the shifting orientation of the Chinese and Russians toward expanding and modernization of nuclear forces, and there is a rising American response to sharply upgrade and better fund its forces, including its store of nuclear weapons.18 Deterrence along old Cold War lines is reemerging, thus promoting, in turn, expansions of nuclear weapons programs in Israel, India, Pakistan, and North Korea as well. The situation in the early 21st century seems to be leaning toward actual use of nuclear weapons for the first time since 1945.

Deterrence efforts often involve weak states and internal fighting partly because of the increasing availability of modern weapons for all sorts of groups disenchanted with the status quo. Thus, deterrence activities in some ways will likely continue to be more violent and lethal in how they are conducted and countered. Western deterrence efforts via military clashes elsewhere are likely to remain low or decline further.

As for deterrence theory, it is changing because it is less cohesive. It will remain in some disarray, providing unsatisfying security understanding and management. There remains no grand theory of why and how deterrence operates to explain its conduct and evolution, and potent adjustments seem unlikely to emerge anytime soon. The actors are too varied, as are the forces and factors bearing down on them and shaping their behavior. Deterrence will remain an insignificant factor in global confrontations, at least for now: leaving us less in command of ourselves and our security despite how specific security threats are detected, confronted, and pursued.


Amadae, S. M. (2016). Prisoners of reason: Game Theory and neoliberal political economy. New York: Cambridge University Press.Find this resource:

Brands, H., & Feaver, P. (2016, November/December). Should America retrench? The battle over offshore balancing. Foreign Affairs, 95(6), 64–69.Find this resource:

Broad, W. J., & Sanger, D. E. (2016). Race for latest class of nuclear arms threatens to revive Cold War. New York Times, April 16.Find this resource:

Brown, M., Cote, O. R., Jr., Lynn-Jones, S. M., Miller, S. E. (Eds.). (2000). Rational choice and security studies: Steven Walt and his critics. Cambridge, MA: MIT Press.Find this resource:

Bryant, W. D. (2015, Winter). Resiliency in future cyber conflict. Strategic Studies Quarterly, 87–107.Find this resource:

Bunn, M. E., & Manzo, A. V. (2011, February). Conventional prompt global strike: Strategic asset or unusable liability? Strategic Forum, pp. 1–23.Find this resource:

Buzan, B., & Hansen, L. (2009). The evolution of international security studies. Cambridge, U.K.: Cambridge University Press.Find this resource:

Dvorkin, V. (2015). Nuclear weapons in Russia’s amended military doctrine, Carnegie Moscow Center. Retrieved on January 22, 2015.

Freedman, (Ed.). (1998). Strategic coercion: Concepts and cases. Oxford: Oxford University Press.Find this resource:

Geist, E. (2015, Winter). Deterrence stability in the cyber age. Strategic Studies Quarterly, 44–62.Find this resource:

Goldstein, A. (2003). An emerging China’s emerging grand strategy: A neo-Bismarckian turn? In G. John Ikenberry & M. Mastanduno (Eds.), International relations theory and the Asia-Pacific (pp. 59–60). New York: Columbia University Press.Find this resource:

Gormley, D. (2015). US advanced conventional systems and conventional prompt global strike ambitions: Assessing the risks, benefits, and arms control implications. Nonproliferation Review, 22(2), 123–139.Find this resource:

Haftendorn, H. (2014). The alliance and the credibility of extended deterrence. In A. A. Michta & P. S. Hilde (Eds.), The future of NATO: Regional defense and global security (pp. 90–111). Ann Arbor: University of Michigan Press.Find this resource:

Klinger, B. (2016). We need a resident who will lead in Asia. Daily Signal, April 4.Find this resource:

Knopf, J. W. (2008, August). Wrestling with deterrence: Bush administration strategy after 9/11. Contemporary Security Policy, 29(2), 229–265.Find this resource:

Knopf, J. W. (2010). The fourth wave in deterrence research. Contemporary Security Policy, 31(1), 1–33.Find this resource:

Libicki, M. (2007). Cyberdeterrence and cvberwar. Santa Monica, CA: RAND.Find this resource:

Libicki, M. (2010). Deterring cyberattacks: Informing strategies and developing options for U.S. policy. Proceedings of a National Research Council Workshop. Washington, DC: National Academies Press.Find this resource:

Mearsheimer, J., & Walt, S. M. (2016, July/August). The case for offshore balancing: A superior grand strategy. Foreign Affairs, 95(4), 70–83.Find this resource:

Morgan, P. (2003). Deterrence Now. New York: Cambridge University Press.Find this resource:

Morgan, P. M. (1990). The US approach to Deterrence. In C. G. Jacobson (Ed.), Strategic power: USA/USSR (pp. 131–139). Basingstoke, U.K.: Macmillan.Find this resource:

(2017, February/March). Survival, 59(1), 103–134.Find this resource:

Morgan, P. (2012). The state of deterrence in international politics today. Contemporary Security Policy, 33(1), 85–107.Find this resource:

(2015). Democracy in the 21st century: Turbulent world, resilient values. International New York Times, September 14.Find this resource:

Powell, R. (1990). Nuclear deterrence theory: The search for credibility. Cambridge, U.K.: Cambridge University Press.Find this resource:

Russett, B. (2009). Deterrence. In Joel Krieger (Ed.), The Oxford companion to politics of the world. New York: Oxford University Press.Find this resource:

Russett, B. (1993). Deterrence. In J. Krieger (Ed.), The Oxford companion to politics of the world (pp. 237–239). New York: Oxford University Press.Find this resource:

Schaub, Gary, Jr. (1998). Compellence: Resuscitating the concept. In L. Freedman (Ed.), Strategic coercion: concepts and cases (pp. 37–60). Oxford: Oxford University Press.Find this resource:

Simon, S., & Stevenson, J. (2015, November/December). The end of Pax Americana: Why Washington’s Middle East pullback makes sense. Foreign Affairs, 94(6), 2–10.Find this resource:

Sokolski, H. D. (Ed.). (2004). Getting MAD: Nuclear Mutual Assured Destruction, its origins and practice. Carlisle, PA: Strategic Studies Institute, U.S. Army War College.Find this resource:

Ven Bruusgaard, K. (2016, August/September). Russian strategic deterrence. Survival, 58(4), 7–26.Find this resource:

Walt, S. M. (2000). Rigor or rigor mortis: Rational choice and security studies. In M. E. Brown, O. R. Cote Jr., S. M. Lynn-Jones, & S. E. Miller (Eds.), Rational choice and security studies: Stephen Walt and his critics. Cambridge, MA: MIT Press.Find this resource:


(1.) Compellence makes someone give in or back down more obviously. Facing a deterrence threat (i.e., “don’t attack or else”) the opponent can say it never intended to attack, not obviously backing down. Facing a threat (i.e., “Stop attacking us now or else” is more difficult politically or psychologically to obey. Both terms are components of “coercive diplomacy.” Compellence remains quite pertinent to deterrence.

(2.) For instance, the Kurds have battled sporadically for years against the leadership of the very countries they live in (Turkey, Iraq, Syria, etc.), demanding a state of their own.

(3.) This sort of situation often arises in the Middle East.

(4.) In the 19th century it was the Concert of Europe, in the 20th century the League of Nations, and later the United Nations.

(5.) Collective actor deterrence is cooperating states collectively upholding peace and security among themselves, in their region (such as NATO), or the global system (such as the UN Security Council) for instance.

(6.) For example, the SU sought to deter Soviet attacks on Western European allies and also attacks on Israel by other states or groups.

(7.) Serious difficulty could lead to unacceptable damage if provoked; this is to make the threat to look sufficiently credible.

(8.) Reportedly Tokyo spent $2 billion and Seoul $900 million supporting the US military presence in their countries in 2015. For planned US force realignments in the Pacific (including new facilities in Guam) those countries will provide $30 billion of a $37 billion total cost. Tokyo has passed a new $44 billion defense budget, and the ROK spends some 2.6% of its GDP now on defense. These are substantial increases. These renewed spending efforts are late in coming, and the amount spent on national defense is much lower than in the United States.

(9.) Roughly 85%, which means many thousands, were eliminated or stockpiled.

(10.) China already had a small number of nuclear weapons for some time and largely froze its arsenal instead.

(11.) This is also true of peacekeeping—it has become more dangerous and less effective. Peacekeeping forces often face suicide attacks, which can readily turn the fighting into more serious combat. Deterrence regarding cyberattacks is important and these days more widely discussed, but there are still problems.

(12.) On a project on deterrence contact Wilner Alexandre, Munk School of Global Affairs and Senior Researcher, ETH Zurich via

(13.) The United States sells or otherwise transfers roughly half the world’s weapons.

(14.) Some parties, of course, ignore these limitations—Russia, Syria, some African governments, for example.

(15.) The Cross Domain Deterrence Project, directed by Erik Gartzke, tracks Cross Domain developments affecting deterrence at the University of California, San Diego. (

(16.) Russian deterrence plans now promote use of nuclear and conventional weapons as acceptable, and this is being discussed in the United States.

(17.) Many Japanese see Pearl Harbor as forced on Japan by US war preparations and intentions, and the war as therefore the United States’ fault.

(18.) The preliminary estimate of US nuclear deterrence forces spending alone for the next 30 years is a trillion dollars.