Freeman Dyson reviews the new biography of Oppenheimer by Ray Monk:

The subtitle, “A Life Inside the Center,” calls attention to a rarer skill in which Oppenheimer excelled. He had a unique ability to put himself at the places and times at which important things were happening.

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Twice I had a reason to talk with him about bombs. The first occasion came in 1958, when I asked for a leave of absence from the institute to work on a project in California aimed at building a nuclear bomb–propelled spaceship. I told him how happy I was to be putting his bombs to better use than murdering people. He did not share my enthusiasm. He considered the spaceship project to be an exercise in applied science, unworthy of the attention of an institute professor. The only activity worthy of an institute professor was to think deep thoughts about pure science. He grudgingly gave me a leave of absence for one year, making it clear that if I stayed away for longer than a year I would not be coming back.

The second occasion for me to talk with Oppenheimer about bombs came a few years later, when I was chairman of the Federation of American Scientists, a political organization of scientists concerned with weapons and arms control. The federation was opposing the US deployment of tactical nuclear weapons in exposed positions in Europe and Asia. We considered these deployments to be unacceptably dangerous, because nuclear-armed troops involved in local fighting could start a nuclear war that would quickly get out of control. When we examined the history of tactical weapons, we learned that Oppenheimer himself had flown to Paris in 1951 to persuade General Eisenhower, then in command of American forces in Europe, that the United States Army needed tactical nuclear weapons to defend Western Europe against a Soviet invasion. Oppenheimer had been enthusiastically promoting the production and deployment of tactical weapons.

After learning this, I went to see Oppenheimer and asked him directly why he had thought that tactical nuclear weapons were a good idea. This time, he answered my question. He said, “To understand why I advocated tactical weapons, you would have to see the Air Force war plan that we had then. That was the God-damnedest thing I ever saw. It was a mindless obliteration of cities and populations. Anything, even a major ground war fought with nuclear weapons, was better than that.”

I understood then how it happened that Oppenheimer came to grief. He was caught in a battle between the Army and the Air Force. The Army wanted small bombs to destroy invading armies. The Air Force wanted big bombs to destroy whole countries. The Army wanted fission bombs and the Air Force wanted hydrogen bombs. Oppenheimer was on the side of the Army. That was why he promoted tactical weapons. That was why he opposed the development of the hydrogen bomb.

The Air Force took its revenge on the Army by helping to drive Oppenheimer out of the government.