Tehran's first semi-official acknowledgment of its atomic ambitions appeared last April, in a bizarre article on the Iranian Revolutionary Guards' Gerdab website. "The day after Iran's first nuclear test is a normal day," read the article, which went on to suggest that far from spelling disaster, the bomb would cause life to go on much as before, except that Iranians would have a little extra national pride.
But Tehran is not alone in downplaying the significance of the country's weapons program. Former U.S. President Jimmy Carter told Time magazine last month that a nuclear Iran wouldn't be "a major catastrophe." Others, such as journalist Fareed Zakaria and Wolfgang Ischinger, a former German diplomat, believe the danger could be contained. "If it was possible to deter the Soviet Union successfully, then that will probably be possible with Iran as well," Mr. Ischinger told the Berliner Morgenpost just ahead of the Feb. 3-5 Munich Security Conference, which he chairs.
As concerns grow that diplomacy and sanctions—including the recent European oil ban—may not stop Iran's nuclear program, it is becoming popular to invoke the Cold War, when the policy of containment managed to avoid all-out war with a nuclear Soviet Union. But the analogy fails on several grounds, and simply accepting the previously unacceptable is not a policy option.
First, the fact that we survived the previous nuclear standoff is hardly evidence that deterrence was bound to succeed. On more than one occasion during the West's struggle with Communism, the threat of mutually assured destruction did not prevent the two sides from stepping right to the brink, most famously during the Cuban Missile Crisis.
It would be a deadly game to try to replay MAD with Iran, in an international environment lacking many of the necessary conditions that helped keep the Cold War from unraveling into chaos. This is not just because mutually assured destruction might be more of an incentive than a deterrent for Mahmoud Ahmadinejad and those around him. Even assuming Tehran will act "rationally," MAD would still be too dangerous to contemplate.
Crucially, a nuclear standoff with Iran would lack a key component that helped keep the Cold War from turning hot: a modicum of mutual trust. Although they were ideological enemies, the Soviet Union and the U.S. had full diplomatic relations and clear channels of communication. Remember those famous red telephones?
Nothing of this sort exists between the U.S. and Israel on one side and Iran on the other. Even in promising to wipe Israel off the face of the earth, Tehran can't even bring itself to so much as call the country by its proper name, referring to it as the "Zionist entity." The absence of direct contacts raises the chance of either side misreading its opponent's intentions.
In addition, Iran lacks second-strike capability and Israel is too small to absorb a nuclear attack. The temptation to launch a preemptive attack will therefore be far greater than that faced by the U.S. and the Soviet Union during the Cold War. Add to that the much shorter flight times for missiles between Iran and Israel than between the U.S. and the Soviet Union—giving both sides much less time to think and react—and the chances for conflict or mishap spiraling out of control grow exponentially. Even if the Iranian regime has no intention of launching an atomic strike, the risks of nuclear war by misinterpretation, technical error or miscalculation could prove unmanageable.
And unlike during the Cold War, in which there were only two main nuclear players, an Iranian bomb would inevitably lead other neighboring states to follow suit, producing a fragile standoff between several actors. Wolfgang Ischinger and other advocates of containment argue that U.S. security guarantees will not only deter Iran but also prevent further nuclear proliferation.
But will any country rely on Western promises to protect them from a nuclear Iran after the same promises failed to curtail a conventionally armed Iran? Countries such as Saudi Arabia, Egypt and Turkey would seek their own nuclear bombs, greatly complicating the game of deterrence. Back in 2008, the International Institute for Strategic Studies reported that at least 13 countries in the greater Middle East had announced new or revived plans to explore civilian nuclear energy. With so many nuclear actors, any of the region's several unresolved conflicts could suddenly become the trigger for a nuclear exchange.
Not to mention that the Iranian regime can circumvent the logic of MAD by passing on a nuclear device to terrorists. Following an atomic attack against a Western city, it would take investigators weeks if not months to determine the culprits, who may never be identified beyond reasonable doubt. It is hard to imagine any Western leader ordering a retaliatory nuclear strike, and thus the deaths of untold numbers of Iranian civilians, on the basis of inconclusive evidence months after the initial attack. Tehran would be quite rational to count on Western scruples in such a case.
The day after Iran's first nuclear test would not be a normal day. Nor could the danger be contained.
—Mr. Schwammenthal is director of the AJC Transatlantic Institute in Brussels.