Do we really want to relive the Cold War nuclear nightmare?

Amid worldwide worries over the prospect of a nuclear-armed Iran and much debate over how to handle it, Barry Posen argues in a New York Times op-ed piece this week that the whole issue is overblown. In his article, headlined "We Can Live With a Nuclear Iran," Posen calmly catalogs the ways in which the widely envisioned threats that stem from this development are, in his view, either "improbable" or easy to "manage" and "defuse."

Posen is a professor of political science at the Massachusetts Institute of Technology and a serious scholar of military affairs. His detailed plan for a U.S. troop withdrawal from Iraq, recently published in the Boston Review, may be the most thoughtful and persuasive analysis on the subject. But I'm not at all convinced by his assurances about Iran.

He first recites the three common fright scenarios on what a nuclear-armed Iran might do: give the weapons to terrorists, blackmail its neighbors (into, say, raising oil prices or shifting their politico-economic policies toward Iranian interests), or engage in outright aggression on the assumption that no one would risk invading or attacking a nuclear state.

I agree with Posen that no state, Iran included, is likely to transfer nuclear weapons to a terrorist group. Such groups can't be controlled or trusted, and if they used the weapons, traces from the fallout could identify the source and retaliation would be certain. I also agree, with him and others, that Iran's primary (but not sole) motive in building nukes is probably to deter an attack by others, principally by the United States. However, the other two scenarios he cites—and a few others that he doesn't consider—are more troubling.

What worries many analysts is not the notion that the Iranian mullahs will launch a deliberate nuclear attack on Jerusalem. (Like Posen, I seriously doubt they would. If they did, Israel, which has many more nukes than Iran might ever accumulate, would obliterate Tehran and much else minutes later. The mullahs may not be rational, as the West understands the term, and they may cheer on suicide bombers; but they are not themselves suicidal, either personally or on behalf of their regime.)

No, the subtler worry—Posen recites it elegantly—is that "a nuclear Iran would simply feel less constrained from other kinds of adventurism, including subversion or outright conventional aggression."

Saddam Hussein reportedly said that his big mistake was to invade Kuwait in 1990 before he'd finished building some nuclear weapons. He had a point. Would the first President Bush have been so fast to repel that invasion if he'd known Iraq had nukes? Would he have been able to hold together such a vast coalition—including all the Arab countries of the region, which sent troops in support? Maybe, maybe not. (It doesn't take many nuclear weapons to deter a foreign invasion, even by a more powerful force. Moscow would almost certainly have invaded China in 1969 if Mao hadn't amassed a handful of nukes a few years earlier.)

Posen knows all these arguments. He is honest enough to recite them faithfully as a prelude to rebutting them—so faithfully that, in the end, his rebuttals raise eyebrows. For instance, he writes:

[T]he fear is that Iran could rely on a diffuse threat of nuclear escalation to deter others from attacking it, even in response to Iranian belligerence. But while it's possible that Iranian leaders would think this way, it's equally possible that they would be more cautious.

Let's stop for a moment. This last sentence could also be written, with no distortion of grammatical meaning: "But while it's possible that Iranian leaders would be more cautious, it's equally possible that they wouldn't be." Posen says, after all, that the two scenarios are "equally possible." (For more on this point, click here.)