So says Arnold Kling over at Econlog.
My reaction isn't very dissimilar from that of Angus at KPC.
In the list of frustratingly popular but completely useless explanations for war, the stupidity of leaders ranks quite well. Along with greed, war-mongering, and intolerance.
And how do we know which leaders are stupid, greedy, intolerant war-mongers, you ask? Why, they're the ones who start wars, of course!
(Arnold cites the Flynn effect, which at least nominally gives us an observable variable (time) with which to explain variation in the occurrence of war. So the above is a little unfair. But seriously. You don't need to point to low IQ to explain why war would occur, nor why wars tend not to go as well as expected. And, as Angus points out, it's hard to take this interpretation of the Flynn effect seriously unless you're willing to make some rather strange claims about human history prior to WWI.)
2 months ago