International relations (IR) is the study of how countries interact with one another on a global stage. It addresses how nations collaborate to address shared challenges like climate change, terrorism and migration – issues that transcend national borders. Diplomacy is at the heart of international relations, as it enables nations to negotiate agreements and resolve conflicts while strengthening relationships among each other.
IR scholars use various theoretical lenses to examine patterns of state behaviour and global phenomena. Realism, liberalism and constructivism are some of the most popular schools of thought. The field also encompasses the study of non-state actors like international institutions, multinational corporations and non-governmental organizations. Viewing international relations at a sub-unit level can have explanatory power when examining issues like religious wars and ethnic conflict, as well as transnational diaspora politics.
In the 20th century, after two world wars, several key themes emerged that transformed international relations. These included an emphasis on balance as the primary framework for international relations, the refusal of any single country to assume a global leadership role and a belief in interdependence as a way to foster cooperation and minimize conflict between nations.
Historically, the study of international relations was considered part of the discipline of political science, but it has evolved into its own multidiscipline and draws on other fields like anthropology, history, geography, law, sociology and philosophy. Its importance has been heightened by the increasing perception that foreign and military policy is an area in which all citizens should be engaged.