American foreign policy since the Korean war has operated in an increasingly complex setting. By early twenty-first century, the pretensions of the sovereign state, acknowledging no authority higher than its own political–moral formulas, had been eroded. The abrading elements included public international agencies, of which the United Nations was premier. Regional economic–political blocs were taking hold, most importantly the European Union. Transnational finance capital leapt political borders. It made nonsense of them, so too imperious multinational companies. Pandemic diseases, AIDS above all, and accelerating ecological deterioration highlighted the state's inability to cope and growing obsolescence. The number of distressed or failed states climbed. A global political culture, meanwhile, gained vitality. It featured increasingly robust courts and laws, human rights norms, plus sundry non-governmental organizations committed to good causes. Politicized religion, manifest in Islamic lands but not restricted to them, added yet another complication to international life. Unaffiliated with states and having shadowy allegiance, terrorist groups achieved more notoriety and lethality, as with the New York–Washington attacks of September 11, 2001 (plus Bali, Madrid, London).

But the nation-state, for good or ill, had proven resilient. The Westphalian order that arose in seventeenth-century Europe from the bloodletting of Protestant–Catholic wars still obtained. Roughly 190 entities laid claim in 2000 to the prerogatives of traditional sovereignty, adorned by diplomatic custom, knit by popular loyalties, validated by tangible control over discrete territories.