Because we secretly want it

This article that I linked to (about the Union widow who died in 2003) deserves a bit more elaboration. Basically, Lee Siegelman notes that the long-term costs of veterans benefits dwarfs the costs of the war itself -- to put it another way, "the wars last longer than the fighting."

Siegelman quotes James L Clayton, from a Nation article in 1969:

Clayton indicated that up to 1967, veterans benefits for the Spanish-American War had amounted to twelve times the original cost of that war, and didn’t peak until 51 years after the war ended; that World War II veterans benefits would probably peak around 2000, and that dependents of Vietnam War veterans would be drawing benefits until the 22nd century.

Also, the cost of debt incurred to fight the war is much larger than the direct cost of the war, leading Clayton to think -- hope? -- that war would eventually become "too expensive to contemplate". Which, funny enough, brings us to a book written just over 50 years before Clayton wrote his article: The Great Illusion, which is often lampooned for having argued that there would never be another major European war. The book had the unfortunate timing of being published in 1912. Of course, the book didn't argue that there would never be another war, but actually argued that there could never be another profitable war among the European powers -- that the wars of the future would be negative-sum games, in which all players were worse off, even the victors. (Like The Limits to Growth, everyone "knows" what this book says, even though almost nobody's actually read it.) And here, Norman Angell was way behind the curve -- does anyone think that the UK profited from the Crimea?

So you could confidently say we've been arguing for over a hundred years now that modern war makes no goddamn sense. I'm not better off, you're not better off, and for damn sure our victims aren't better off. These are facts: if you don't need to fight a war, only madmen think it's a good idea to. These people should be regarded with the same disdain and pity you would regard any other lunatic claiming to be Napoleon.

But war will never be too expensive, too foolish, or too bloodthirsty to contemplate. Like Hollywood blockbusters or financial speculation, there's always some new, really new, this-time-it's-different-new reason that we've just got to get in on the action. Because this time, our enemy is more implacable than our previous foes, or he has worse weapons, or he believes in a different sky fairy, or whatever. War is inevitable.