Back in 2009, when there was (briefly) a policy consensus in favor of active fiscal policy to fight the economic slump, there were many warnings to the effect that we must not repeat the infamous mistake of 1937, in which President Franklin D. Roosevelt was persuaded to focus on balancing the budget while the economy was still weak, terminating the recovery and sending the United States into the second leg of the Great Depression. And what policy makers proceeded to do was, of course, to repeat the mistake of 1937.