# Unilateralism A state acting alone in international affairs — without seeking consensus from allies, authorization from international institutions, or agreement from affected parties. Unilateral action can range from withdrawing from treaties and imposing sanctions to launching military operations without allied participation or UN authorization. The term is descriptive rather than inherently pejorative, but in practice it carries the implication that the acting state has chosen its own judgment over collective decision-making. ## American unilateralism The United States has oscillated between [[Multilateralism]] and unilateralism throughout its history, but the post-Cold War period has seen a pronounced rightward shift toward unilateral action. Key inflection points include: the 2003 Iraq invasion (launched without UN Security Council authorization, justified by the [[Bush Doctrine]] of preventive war), the withdrawal from the Kyoto Protocol (2001), the withdrawal from the Paris Climate Agreement (2017), the withdrawal from the Iran nuclear deal (JCPOA, 2018), the withdrawal from the WHO (2020), and the imposition of tariffs under national security authorities without allied coordination. The intellectual case for American unilateralism rests on two arguments the vault tracks across multiple domains. First, the sovereignty argument: that international institutions constrain American freedom of action in ways that an elected government should not accept. Second, the power argument: that the United States is strong enough to achieve its objectives alone and should not dilute its leverage by submitting to collective processes that give smaller or adversarial states a voice. ## The pattern Unilateralism tends to correlate with the concentration of decision-making in the executive branch, since unilateral action bypasses the legislative and institutional processes that multilateral commitments require. The vault's coverage of [[Unitary Executive Theory]] and [[Signing Statements]] maps the domestic constitutional dimension of the same impulse: the preference for unconstrained executive action over institutional negotiation. ## See Also - [[Multilateralism]] — the collective alternative - [[Bilateralism]] — the two-party middle ground - [[Multipolar World]] — the emerging order that raises the costs of going it alone - [[Isolationism]] — the deeper tradition of disengagement - [[American Exceptionalism]] — the belief framework that justifies exempting the U.S. from international constraints