I like how Jonathan Chait wrote a whole book accusing right-wingers of braindead supply-sider free-lunchism and now induldges in left-winger braindead demand-side free-lunchism with all the zeal of bizarro Jack Kemp on meth.
I mean, check it out!
The point of stimulus spending … is simply to spend money–on something useful if possible, wasteful if necessary. Keynes proposed burying money in mineshafts, so that workers would be hired to dig it out. (Imagine what the GOP could do with material like that.) World War II was an effective stimulus that, economically speaking, consisted of 100 percent waste. If war hadn't broken out, we could have enjoyed the same economic benefit by building all those tanks and planes and dumping them into the ocean.
Oh my. Since Chait's a pure empiricist with no agenda but truth, I'm sure he'll be receptive to the facts revealed in Robert Higgs' Depression War and Cold War. Here's Price Fishback's summary.
[UPDATE: Also see Tyler Cowen.]