President Obama has been accused of acting like a monarch. But the US presidency has been an elected kingship since 1776 in all but name, argues the historian David Cannadine.

After five weeks of campaigning, which may have seemed unending and interminable at the time, but which in retrospect passed relatively quickly, the British general election is over, and David Cameron is once again ensconced in 10 Downing Street. But although the votes will not be cast until November 2016, the battle for the American Presidency has already begun, as several Republicans and Democrats, with varying degrees of plausibility, have recently declared themselves as candidates for their party's nomination. Yet there are 18 months to go until that election, and Barack Obama will not actually vacate the White House until his successor is inaugurated in Washington DC in January 2017. This is, to put it mildly, a much longer period of campaigning than that which characterises British elections, and it's often observed that the abilities required to win the long-distance race for the American Presidency are very different from those that are subsequently needed to govern the country from the Oval Office.