During the last financial crisis it turned out to be a stroke of good fortune that the governor of the US federal reserve was a historian of the Great Depression. The lesson of history, Ben Bernanke believed, was that allowing a crisis to turn into a sustained meltdown of the system was so destructive that policymakers should use every tool available to avoid a repeat.

In 1929 a failure to act helped to crash the German banking system, supercharged fascism and created the conditions for a war that cost more than 50 million lives. With that in mind, think how much worse the populist surge of recent years could have been post-2008 without action. Even a critic of bailing out banks such as me can