P.M. Prescott had a good post responding to my post about militaristic Keynesianism. He made some good points, in particular, about the slightly dystopian shape such a stimulus method might take.
There’s no doubt in my mind that it’s a sub-optimal way of achieving a Keynesian stimulus; and it’s even possible it could be more trouble than it’s worth, as military build-ups themselves sometimes lead to wars. Even if that were averted, we run the risk of becoming a militaristic, Spartan–or worse, decadent Roman–society if vastly more military spending were pursued.
Obviously, it’s much less painful to just pay for increased benefits to the poor, and some infrastructure projects. But, as Krugman and Prescott both rightly show, the more fantastic and dire scenarios are a more politically realistic means. That’s rather depressing.