One of my teachers, a former chief of Israeli military intelligence, used to say that going to war is not like asking a girl out on a date. It is a very serious decision, to be made on the basis of carefully crafted answers to even more carefully crafted questions.

Some serious questions, then, about whether the United States should bomb Iran's nuclear installations.

The first and most obvious question is whether it is worth doing in the first place. Starting right after Hiroshima, each time a country was about to go nuclear Washington went out of its way to sound the alarm, warning of the dire consequences that would surely follow. From 1945 to 1949 it was the Soviet Union which, once it had succeeded in building nuclear weapons, was supposed to make an attempt at world conquest.

In the 1950s it was America's own clients, Britain and France, who were regarded as the offenders and put under pressure. Between 1960 and 1993, first China, then Israel (albeit to a limited extent) and finally India and Pakistan were presented as the black sheep, lectured, put under pressure and occasionally subjected to sanctions. Since then, the main victim of America's peculiar belief that it alone is sufficiently good and sufficiently responsible to possess nuclear weapons has been North Korea.

As the record shows, in none of these cases did the pessimists' visions come true. Neither Stalin, Mao nor any of the rest set out to conquer the world. It is true that, as one country after another joined the nuclear club, Washington's ability to threaten them or coerce them declined.

However, nuclear proliferation did not make the world into a noticeably worse place than it had always been — and if anything, to the contrary. As Europe, the Middle East and South Asia demonstrate quite well, in one region after another the introduction of nuclear weapons led, if not to brotherhood and peace, then at any rate to the demise of large-scale warfare between states.

Given the balance of forces, it cannot be argued that a nuclear Iran will threaten the United States. Iranian President Mahmoud Ahmadinejad's fulminations to the contrary, the Islamic Republic will not even be a threat to Israel. The latter has long had what it needs to deter an Iranian attack....