The US's clear military and economic dominance of the postwar world gave it an obvious claim to seniority; however, there was also a strong strain within English conservatism at the time that saw itself as Greeks in this American empire, in the words of former Tory prime minister Harold Macmillan. In other words, even if the Americans were to be the new Romans, extending their dominion over every corner of the globe, without the intellectual, cultural and political guidance of their wise old mother country they would quickly fall into ruin.
That may sound counterintuitive. After all, the US has kidnapped a foreign leader, and Donald Trump has announced that he will run Venezuela. Surely this looks less like decay than intoxication: a superpower high on its own force. But Trump's great virtue, if it can be called that, is candour. Previous US presidents draped naked self-interest in the language of democracy and human rights. Trump dispenses with the costume.