Compounding the challenges facing the next US president is the transition from the old administration to the new. This is no small matter. American handover arrangements would strike politicians and civil servants in many other countries, especially Britain, as odd at the best of times. Under present conditions they are downright hazardous.

The new president will not be inaugurated until January 20, 11 weeks after the election. Moreover, the US system calls for the entire executive branch to be purged several layers deep when a new chief executive takes over: there is no permanent senior civil service after the British fashion. This vast reshuffle typically takes months. In some cases, if Congress is reluctant to co-operate in confirming appointments, it is never concluded.