The End of the Post–Cold War Era and the Return of Hard Power
After 1991 the post–Cold War international order was built on U.S. primacy, liberal institutions, and the expectation of a durable peace in Europe. U.S. strategy documents from 1992 onward (e.g. the leaked Defense Planning Guidance) explicitly foresaw an “unchallenged supremacy” for America[1] and a liberal order topped by the United States. American policymakers sought to “cultivate an open, democratic order in which [the U.S.] remained firmly atop the international hierarchy”[1]. In practice this meant NATO remained central: the alliance was expanded eastward to lock in Europe’s security under U.S. leadership[2][1]. NATO enlargement proceeded in stages (1999, 2004, 2009, 2017/20) as former Warsaw Pact countries joined, reflecting the assumption that a “whole and free Europe” should be achieved under Western auspices[2][3].
At home in Europe, this era saw a “peace dividend” as countries cut military budgets for new spending on welfare and integration. Most European NATO members spent well below Cold War levels, relaxing conscription and redirecting resources to social programs. One analysis finds that Europe’s governments “collected the peace dividend of 1.8 trillion Euro” (relative to NATO’s 2%-of-GDP target) between 1991 and 2021[4]. For example, many Western armies shrank and closed bases in the 1990s and 2000s, often citing the end of direct threats after 1991. The strategic assumption was that great-power war had become unlikely and the West could “actively maintain” the liberal order[1] rather than militarily prepare for it. In short, the 1991–2021 period was characterized by U.S. hegemony, NATO’s enlargement as a keystone of security policy[2][3], and a broad cutback in defense across Europe as the alliance embraced liberal integration and collective security under American leadership.