By Fareed Zakaria, CNN

We are hearing a new concept these days in discussions about Iran — the zone of immunity. The idea, often explained by Ehud Barak, Israel’s defense minister, is that soon Iran will have enough nuclear capability that Israel would not be able to inflict a crippling blow to its program.

Israeli officials explain that we Americans cannot understand their fears, that Iran is an existential threat to them. But in fact we can understand because we have gone through a very similar experience ourselves. After World War II, as the Soviet Union approached a nuclear capability, the United States was seized by a panic that lasted for years.Everything that Israel says about Iran now, we said about the Soviet Union.

We saw it as a radical, revolutionary regime, opposed to every value we held dear, determined to overthrow the governments of the Western world in order to establish global communism. We saw Moscow as irrational, aggressive and utterly unconcerned with human life. After all, Joseph Stalin had just sacrificed a mind-boggling 26 million Soviet lives in his country’s struggle against Nazi Germany.

Just as Israel is openly considering preemptive strikes against Iran, many in the West urged such strikes against Moscow in the late 1940s. The calls came not just from hawks but even from lifelong pacifists such as the public intellectual Bertrand Russell.

To get a sense of the mood of the times, consider this entry from the Nov. 29, 1948, diary of Harold Nicolson, one of the coolest and most sober British diplomats of his generation: “[I]t is probably true that Russia is preparing for the final battle for world mastery and that once she has enough bombs she will destroy Western Europe, occupy Asia, and have a final death struggle with America. If that happens and we are wiped out over here, the survivors in New Zealand may say that we were mad not to have prevented this. . . . There is a chance that the danger may pass and peace can be secured with peace. I admit it is a frail chance, not one in ninety.”

In a speech at the Boston Navy Yard in August 1950, Navy Secretary Francis Matthews argued that, in being “an initiator of a war of aggression,” the United States “would become the first aggressors for peace.”

In the end, however, the global revolutionaries in Moscow, the mad autocrats in Pyongyang and the terrorist-supporting military in Pakistan have all been deterred by mutual fears of destruction. While the Iranian regime is often called crazy, it has done much less to merit the term than did a regime such as Mao’s China. Over the past decade, there have been thousands of suicide bombings by Saudis, Egyptians, Lebanese, Palestinians and Pakistanis, but not been a single suicide attack by an Iranian. Is the Iranian regime — even if it got one crude device in a few years — likely to launch the first?

The efforts to delay and disrupt Iran's nuclear program are working. But even if one day Tehran manages to build a few crude bombs, a policy of robust containment and deterrence is better to contemplate than a preemptive war.

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