Why Keynesians love WWII, and should love Romney

Economists still debate what ended the Great Depression but for Keynesians it was the mass mobilisation of WWII that provided the ultimate 'stimulus' for recovery. The argument implies that its proponents may have a predilection towards military spending. If depressions are caused by underconsumption, and the resulting loss of productive capacity in an economy can be prevented by boosting aggregate demand through deficit-financed government spending, then presumably Keynesians would prefer to stimulate consumption in a way that does not also add to production capacity, because that would make it harder to close the output gap between demand and supply. Hence the proposal to pay workman to dig holes and fill them up again. But what better way is there to stimulate aggregate demand in the near term without adding to capacity in the long run than spending on the production of things that get blown up in a war? Enter Mitt Romney who plans to raise US defence spending to $7.9 trillion over the next ten years, $2.1 trillion more than the current Pentagon budget.