A few years ago, it would have been remarkable for any senior US politician to demand the head of the chairman of the US Federal Reserve. During last week’s Republican debate, almost all of the hopefuls cheerfully called for Ben Bernanke’s.

Rick Perry wisely refrained from repeating his threat to treat the “almost treasonous” Mr Bernanke “pretty ugly down in Texas”. Most of the rest, including Mitt Romney, the only viable moderate among them, were happy to put the boot in. “I’d be looking for somebody new,” he said.

Fed watchers remind us that populist anger against America’s central bank rises and falls with the business cycle. At the height of the late 1990s boom Alan Greenspan was hailed as a magician. During the early 1990s, the future “maestro” was pilloried as a monetary scrooge.