העורך Editor

Once upon a time wars were fought for fun and profit; when Rome overran Asia Minor or Spain conquered Peru, it was all about the gold and silver. And that kind of thing still happens. In influential research sponsored by the World Bank, the Oxford economist Paul Collier has shown that the best predictor of civil war, which is all too common in poor countries, is the availability of lootable resources like diamonds. Whatever other reasons rebels cite for their actions seem to be mainly after-the-fact rationalizations. War in the preindustrial world was and still is more like a contest among crime families over who gets to control the rackets than a fight over principles.

If you’re a modern, wealthy nation, however, war — even easy, victorious war — doesn’t pay. And this has been true for a long time. In his famous 1910 book “The Great Illusion,” the British journalist Norman Angell argued that “military power is socially and economically futile.” As he pointed out, in an interdependent world (which already existed in the age of steamships, railroads, and the telegraph), war would necessarily inflict severe economic harm even on the victor. Furthermore, it’s very hard to extract golden eggs from sophisticated economies without killing the goose in the process.

We might add that modern war is very, very expensive. For example, by any estimate the eventual costs (including things like veterans’ care) of the Iraq war will end up being well over $1 trillion, that is, many times Iraq’s entire G.D.P.

So the thesis of “The Great Illusion” was right: Modern nations can’t enrich themselves by waging war. Yet wars keep happening. Why?

One answer is that leaders may not understand the arithmetic.

Angell, by the way, often gets a bum rap from people who think that he was predicting an end to war. Actually, the purpose of his book was to debunk atavistic notions of wealth through conquest, which were still widespread in his time. And delusions of easy winnings still happen. It’s only a guess, but it seems likely that Vladimir Putin thought that he could overthrow Ukraine’s government, or at least seize a large chunk of its territory, on the cheap — a bit of deniable aid to the rebels, and it would fall into his lap.

And for that matter, remember when the Bush administration predicted that overthrowing Saddam and installing a new government would cost only $50 billion or $60 billion?

The larger problem, however, is that governments all too often gain politically from war, even if the war in question makes no sense in terms of national interests.

Recently Justin Fox of the Harvard Business Review suggested that the roots of the Ukraine crisis may lie in the faltering performance of the Russian economy. As he noted, Mr. Putin’s hold on power partly reflects a long run of rapid economic growth. But Russian growth has been sputtering — and you could argue that the Putin regime needed a distraction.

Similar arguments have been made about other wars that otherwise seem senseless, like Argentina’s invasion of the Falkland Islands in 1982, which is often attributed to the then-ruling junta’s desire to distract the public from an economic debacle. (To be fair, some scholars are highly critical of this claim.)

And the fact is that nations almost always rally around their leaders in times of war, no matter how foolish the war or how awful the leaders. Argentina’s junta briefly became extremely popular during the Falklands war. For a time, the “war on terror” took President George W. Bush’s approval to dizzying heights, and Iraq probably won him the 2004 election. True to form, Mr. Putin’s approval ratings have soared since the Ukraine crisis began.

No doubt it’s an oversimplification to say that the confrontation in Ukraine is all about shoring up an authoritarian regime that is stumbling on other fronts. But there’s surely some truth to that story — and that raises some scary prospects for the future.

And if authoritarian regimes without deep legitimacy are tempted to rattle sabers when they can no longer deliver good performance, think about the incentives China’s rulers will face if and when that nation’s economic miracle comes to an end — something many economists believe will happen soon.

Remember, this is also the man who believes catastrophe increases wealth. At least he doesn’t think so of war (in the final analysis); assuming his writing reflects his convictions at the time (always doubtful, as can be seen from a careful reading of his intellectual history).