Unilateralism is any doctrine or agenda that supports one-sided action. Such action may be in disregard for other parties, or as an expression of a commitment toward a direction which other parties may find disagreeable. As a word, unilateralism is attested from 1926, specifically relating to unilateral disarmament. The current, broader meaning emerges in 1964. It stands in contrast with multilateralism, the pursuit of foreign policy goals alongside allies.
Unilateralism and multilateralism represent different policy approaches to international problems. When agreement by multiple parties is absolutely required—for example, in the context of international trade policies—bilateral agreements (involving two participants at a time) are usually preferred by proponents of unilateralism.