Multilateralism, Bilateralism and Unilateralism in Foreign Policy
This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Politics. Please check back later for the full article.
Diplomacy can be conducted through a variety of mechanisms. While there have been numerous attempts to create an appropriate categorization of the types of diplomacy, international relations scholars have long been working on how diplomacy can be understood by distinguishing diplomatic interactions as parts of multilateralism, bilateralism and unilateralism.
The numerical approach simply focuses on the numbers of countries involved. Multilateralism in the numerical sense needs more than three states in interactions; bilateralism needs two states; and unilateralism can be pursued by only a single state. However, there are more quality-oriented approaches to distinguish these interactions. For instance, multilateralism, which requires states to follow international norms and pay more respect to international institutions, can be contrasted with unilateralism, where a single state can influence how international relations can be conducted. Therefore, to understand multilateralism in foreign policy, we need to understand how international society has developed institutions, norms, and regimes. By contrast, studies on unilateralism tend to focus on how a powerful state conducts its foreign policy by neglecting international institutions and legal constraints. In this regard, multilateralism and unilateralism in the use of force and economic sanctions, where institutions and legal constraints have rapidly developed after the Second World War, are important and interesting topics to cover.
Other than the use of force and economic sanctions, there has been an accumulation of evidence-based research on how multilateralism, bilateralism, and unilateralism differentiate outcomes of foreign policy such as international aid, financial policy coordination, and environmental cooperation.