The unipolar moment & post-9/11 world
From Soviet collapse (1991) to the War on Terror: the unipolar moment, humanitarian interventionism, and the erosion of US primacy through Iraq, Afghanistan and 2008.
The end of bipolarity
The Cold War ended not with a treaty but with a sequence of collapses. The Berlin Wall fell on 9 November 1989; the Conventional Forces in Europe (CFE) Treaty was signed on 19 November 1990; the Warsaw Pact dissolved on 1 July 1991; and on 26 December 1991 the Supreme Soviet of the USSR formally recognised the dissolution of the Soviet state, leaving the Russian Federation under Boris Yeltsin as its successor and sole holder of the UN Security Council permanent seat. The United States stood as the only superpower, possessing global military reach, the reserve currency, and an alliance system (NATO, the US-Japan Security Treaty) that had no peer competitor.
Krauthammer's thesis
The phrase "unipolar moment" was coined by Charles Krauthammer in Foreign Affairs (Winter 1990/91). His argument: the post-Cold-War world was not multipolar but unipolar, with the United States at the apex, and this distribution would last decades unless squandered. Francis Fukuyama's The End of History? (National Interest, 1989; book 1992) supplied the ideological companion: liberal democracy and market capitalism as the terminal point of ideological evolution. George H. W. Bush proclaimed a "New World Order" in his 11 September 1990 address to Congress.
The first test: the Gulf War
The new order's first demonstration was the response to Iraq's invasion of Kuwait on 2 August 1990. UN Security Council Resolution 660 (2 August 1990) demanded withdrawal; Resolution 678 (29 November 1990) authorised "all necessary means" after 15 January 1991. Operation Desert Storm (17 January–28 February 1991) liberated Kuwait through a US-led coalition of 35 nations, operating under explicit UN authority—the textbook case of collective security functioning as the UN Charter (Chapter VII) intended, now that superpower veto-deadlock had lifted.
Expansion and intervention
The 1990s saw NATO enlargement (Poland, Hungary, the Czech Republic admitted 1999), the creation of the World Trade Organization (1 January 1995), and the European Union via the Maastricht Treaty (signed 7 February 1992). Yet the decade also exposed the limits of liberal triumphalism. The Rwandan genocide (April–July 1994) killed roughly 800,000 while the international community failed to act; the Srebrenica massacre (July 1995) occurred in a UN-declared "safe area." NATO's Operation Allied Force over Kosovo (24 March–10 June 1999) was conducted without Security Council authorisation, justified on humanitarian grounds—a precedent that fed the later "Responsibility to Protect" (R2P) doctrine, endorsed at the 2005 UN World Summit. The unipolar moment thus combined unmatched American power with recurring crises that primacy alone could not resolve.
