I think I can only reasonably talk about American history in this thread, but 1945-1950 may not be our most influential time period. There's an argument for the four year period til 1949 but that period was marked by the onset of the Cold War, an uncertain economy with a dip in per capita income, Soviet atom bombs and Chinese unification under the Communists. I'd point toward ten years after, from around 1956-1962. The US saw unprecedented economic growth, cemented its place as leader of the West with the decolonization of the French and British Empires, saw military power on the upswing with an accompanying increase in boldness against the Eastern Bloc, and cultivated East Asia against the communists in North Korea and Japan. Certainly the Soviets saw victories then as well, like the Cuban Revolution, but Americans were ready for a struggle - a far cry from detente or the Vietnam War. Late 80s/early 90s with fall of the USSR, second Gulf War gave the Americans some sense of victory, of being a superpower, but relative political influence and economic prosperity might've peaked back in the 50s.