Shashank Joshi warns that nuclear alarmism on both sides of the Atlantic “could drag us into an unwinnable and unnecessary war.”

A nuclear Iran is profoundly undesirable – but it’s also eminently containable.

The … argument, that Iran is too crazy to be deterred, is historically untenable. Stalin’s Soviet Union was viewed in exactly the same terms. NSC-68, one of the most famous American intelligence assessments of the cold war, judged Moscow to be “animated by a new fanatic faith, antithetical to our own”, aimed at “domination of the Eurasian landmass”. That was the year after the Soviets’ first nuclear test. Mao Zedong, who was to acquire a bomb shortly thereafter, welcomed a nuclear war in which “imperialism would be razed to the ground, and the whole world would become socialist”.

Senator Joseph Lieberman last week fumed that “containment might have been viable for the Soviet Union during the cold war, but it’s not going to work with the current fanatical Islamist regime in Tehran”. Well, fanaticism has pedigree. Stalin and Mao might have been bloodthirsty fanatics, but they were not suicidal. Nor is Mahmoud Ahmadinejad.

Last week, two of America’s top intelligence officials told a senate hearing two important things. First, any Iranian decision to build a nuclear weapon would be based “on a cost-benefit analysis”. Even fanatical theocracies are governed by reason. Second, “Iran is unlikely to initiate or intentionally provoke a conflict”. If Iran is deemed to be unlikely to start a conventional war, it’s not going to start a nuclear war.

And there’s a simple reason for this. The area around Tehran contains a fifth of Iran’s population, and half of the country’s industry. A single Israeli thermonuclear bomb would wipe this out in the blink of an eye. Iran’s abhorrent calls to wipe Israel off the map are gestures as empty as Mao’s nuclear posturing.