When I was in school learning macro 101 from Baumol and Blinder, my memory is that the theory of Keynesian stimulus and managing the economic cycle was that deficits should be run in the bottom part of the economic cycle, paid for with surpluses in the top half. So we are now almost certainly in the top half of the cycle. But I don't hear any Keynesians seeking to run a surplus, or even to dial back on government deficits or spending. In fact, our Keynesian-in-chief says he is done with "mindless austerity" and wants to start spending even harder in 2015.
Its enough to make one suspicious that all the stimulus talk is just a Trojan Horse for a desire to increase the size and power of government.
But for Keynesians who really believe what they are saying, that deficit spending somehow saved us from a depression in 2009 and 2010, then I ask you -- what are you going to do next time? It appears that when we enter the next recession in this country, that US debt as a percentage of GDP is going to be almost twice what it was entering the last recession. Don't you worry that this limits your flexibility and ability to ramp up deficit spending in the next recession?
The situation in the US is the same as it is worldwide. While those evil private short-term-focused private actors have used the improving economy to de-leverage back below 2007 levels, governments have increased their debt as a percentage of GDP by just over 50% since just before the last recession.
Since 2007, according to my old friends at McKinsey, global government debt has risen by $25 trillion since 2007. If you really care about Keynesian stimulus in recessions, and not just "mindlessly" (I can use that term too) increase government spending, wouldn't you want to be building up some reserves for next time?