When Tim Geithner arrived to take over the presidency of the New York Fed in 2003, he asked the staff there to give him tutorials for an hour each day on macroeconomics to enable him to learn the necessary skills as fast as he could. Although he does not possess any formal degrees in economics, this sort of preparation has helped give him an impressive grasp of the key issues.

For Mr Geithner, above all else, the idea of serving in public office is about trying to do the best job – or, as he would joke, “the least bad possible” – with whatever hand fate provides. He is not somebody, in other words, who spends hours theorising about what could or should have been done according to any policy textbook; his focus is always on results, and to get them he will collect ideas, advice and opinions from wherever he can.