SPY EYES

In 1980, Saddam Hussein invaded Iran. He reckoned Iranians were too divided by their year-old revolution to offer much riposte. Wrong: Iranians were galvanized, the last internal opposition to Ayatollah Khomeini’s theocracy was quashed, and Iran stood as one to face the enemy.

There’s no need to look much further to know how Tehran would respond if Israel or the United States bombed Iran in an attempt to halt its nuclear program. An Iranian society that today is a combustible mix of depression, division and dysfunction — overseen by a Brezhnevian supreme leader at loggerheads with his erratic president — would unite in fury.

This, in the cautionary words of U.S. Defense Secretary Leon Panetta, could have “unintended consequences.” Among them: a lifeline for the weakened Islamic Republic that would lock it in for a generation; a sharp rise in American dead in neighboring Iraq and Afghanistan; direct or indirect (through Hezbollah) retaliation against Israel; a wave of radicalization just when jihadist ideology seems tired and the Arab Spring stands at a delicate juncture; a blow to the global economy from soaring oil prices; a revival of Iran’s sagging regional appeal as it becomes yet another Muslim country to face Western bombs; increased terrorism; and a subsequent Iranian race for a nuclear weapon fired by resentments as indelible as those left by the C.I.A. coup that ousted Prime Minister Mohammed Mossadegh in 1953.

This is not an appealing proposition. But nor of course is a nuclear Iran. And there’s the rub.

Like a bad movie, the Iranian nuclear crisis keeps returning. We’re now at the sequel of the sequel of the sequel. Graham Allison, a Harvard professor and leading security strategist, has compared it to a “Cuban missile crisis in slow motion.”

As they have for many years now, Israeli leaders are warning that the time to avert a military strike is running out; Republican presidential candidates strain for more all-out bellicosity toward Tehran; Iran continues its puzzling decades-long crabwalk toward some military-nuclear threshold; and the International Atomic Energy Agency finds credible evidence of work on a deliverable bomb.

Even in slow motion, this is no game for amateurs. Loony schemes like the Orwellian “Iran Threat Reduction Act” before Congress that would make contact with Iranian officials illegal only foment a dangerous jingoism.

I see four key elements. First, Iran is not fiddling around with nuclear triggers and high-precision detonators because it wants to generate electricity. It seeks a military-nuclear capability common to its region (Israel, Pakistan, India and Russia).

Second, its halting progress toward this goal, far slower than Pakistan’s, relates not only to effective countermeasures (Stuxnet, dead scientists) but also to a deep-seated inertia and ambiguity; Ali Khamenei, the supreme leader, is the “guardian of the revolution” and as such in a conservative business where he will be judged on the Islamic Republic’s survival. The nuclear program is nationalistic glue for a fragile society even if it goes nowhere.

Third, Iran, shaken by the 2009 uprising, a young nation with a stale revolutionary regime, is uneasy: a feverish demand for hard currency has pushed the unofficial dollar rate way above the official one, prices for staples are soaring, a huge banking scandal has underscored rampant corruption, and the tensions between the Islamic Republic’s divine superstructure (Khamenei) and its (fraudulently) elected president, Mahmoud Ahmadinejad, are virulent.

Fourth, the big loser from the Arab Spring has been Iran because the uprisings are about accountability and representation, which is precisely what the Iranian Revolution denied its authors after promising freedom. Nobody finds inspiration in the Iranian model.

In short, the leaders of the Islamic Republic — but emphatically not the Iranian people — are the West’s enemy, and Iran seeks nuclear weapons capability. But the country is hesitant and divided; and it does not want war. Khamenei is aging; how he would be replaced is unclear. Another presidential election in a couple of years will again reveal the Islamic Republic’s paralyzing contradictions.

These circumstances give the United States and Israel room for effective action, so long as they resist a rash military strike. The aim should be to increase Iran’s internal divisions, not unite it in furious resolve.

In 1946, when he wrote the “Long Telegram” that birthed the policy of containment, George Kennan observed a Soviet Union that was also an ideological enemy of the West, but overstretched and economically weak. He judged, correctly, that it could be contained through firmness, as it was even after developing a bomb.

Iran, more unpredictable than the Soviet Union, can be stopped short of a bomb through measures short of military action. What is needed is a contain-and-constrain policy. Contain Iran through beefed-up Israeli and Gulf defenses, a process underway. Constrain it to circle in its current nuclear ambiguity through covert undermining (Stuxnet 2.0, etc.), tough measures to block its access to hard currency, and, as a last resort, a “quarantine” similar to John Kennedy’s interdiction of shipping to Cuba during the missile crisis.

How you judge patience depends on how you judge time. Time is not on the Islamic Republic’s side.