New historical research in fact lends powerful support to the traditionalist interpretation of the decision to drop the bomb. This conclusion may surprise Guardian readers. The so-called revisionist interpretation of the bomb made headway from the 1960s to the 1990s. It argued that Hiroshima and Nagasaki were less the concluding acts of the Pacific war than the opening acts of the cold war. Japan was already on the verge of surrender; the decision to drop the bomb was taken primarily to gain diplomatic advantage against the Soviet Union.

Yet there is no evidence that any American diplomat warned a Soviet counterpart in 1945-46 to watch out because America had the bomb. The decision to drop the bomb was founded on the conviction that a blockade and invasion of Japan would cause massive casualties. Estimates derived from intelligence about Japan’s military deployments projected hundreds of thousands of American casualties.

It will be interesting to see what sort of response Mr. Kamm’s article elicits. I predict howls of rage and vituperation. But he is right:

Hiroshima and Nagasaki are often used as a shorthand term for war crimes. That is not how they were judged at the time. Our side did terrible things to avoid a more terrible outcome. The bomb was a deliverance for American troops, for prisoners and slave labourers, for those dying of hunger and maltreatment throughout the Japanese empire - and for Japan itself. One of Japan’s highest wartime officials, Kido Koichi, later testified that in his view the August surrender prevented 20 million Japanese casualties. The destruction of two cities, and the suffering it caused for decades afterwards, cannot but temper our view of the Pacific war. Yet we can conclude with a high degree of probability that abjuring the bomb would have caused greater suffering still.

Read the whole thing here.

What is the essence, the core, of conservative wisdom? One part is that when it comes to the real world, the choices we face are often not between good and bad but between bad and worse. This is particularly true in times of war. A difficult lesson. But crucial for those who wish to do good as well emit good-sounding slogans.