At the end of the second world war, 43 allied nations gathered at Bretton Woods to reconstruct the global financial system. The result was an economic version of Pax Americana: a liberal trading and financial regime centred on US strength. The dollar became the world’s reserve currency and the free world fixed its exchange rates to the greenback. Europe and Japan proceeded to rebuild their economic base, in large part by exporting to the US and accumulating international reserves.While it lasted, Pax Americana had great symbiotic benefits for the US and its allies. Fixed exchange rates jump-started postwar trade and finance. Over time, however, the dollar’s hegemony was gradually eroded by large trade deficits, rising inflation and the exploding costs of funding both Lyndon Johnson’s ‘Great Society’ welfare programme and the Vietnam war.