A main school of international relations. Seeks to achieve lasting peace and cooperation in international relations. Liberalists reject Realism's argument that peace cannot exist. Instead they use a variety of peace theories to show how peace can be achieved. Among these are the Democratic Peace Theory which states that liberal democracies do not go to war with one another; the Commercial Peace Theory which argues that free trade has pacifying effects on international relations; Institutional peace theory, which attempts to demonstrate how cooperation can be sustained in anarchy through international institutions.