In his disproportionate praise of the six-month agreement with Iran, Barack Obama said: “For the first time in nearly a decade, we have halted the progress of the Iranian nuclear program.” But if the program, now several decades old, had really been “halted” shortly after U.S. forces invaded neighboring Iraq, we would not be desperately pursuing agreements to stop it now, as about 10,000 centrifuges spin to enrich uranium.

If Denmark wanted to develop nuclear weapons, we would consider that nation daft but not dangerous. Iran’s nuclear program is alarming because Iran’s regime is opaque in its decision-making, frightening in its motives (measured by its rhetoric) and barbaric in its behavior. “Manes,” writes Kenneth M. Pollack of the Brookings Institution, “from whose name the word manichean derives, was a Persian who conceived of the world as being divided into good and evil.” But Pollack says suicidal tendencies are not among the irrationalities of the Iranian leadership, who are not “insane millenarians.”

In “Unthinkable: Iran, the Bomb, and American Strategy,” Pollack argues that Iran’s nuclear program has been, so far, more beneficial to the United States than to Iran. Because of the anxieties and sanctions the program has triggered, Iran is more isolated, weak, impoverished and internally divided than at any time since it became a U.S. adversary in 1979. And one possible – Pollack thinks probable – result of Iran acquiring a nuclear arsenal would be Saudi Arabia doing so. Pollack considers this perhaps “the most compelling reason” for Iran to stop just short of weaponization.

Writing several months before the recent agreement was reached, Pollack said that, given Iran’s adamant refusal to give up all enrichment, it will retain at least a “breakout capability” – the ability to dash to weaponization in a matter of months, even weeks. Hence the need to plan serious, aggressive containment.

In September 2012, the Senate voted 90-1 for a nonbinding resolution “ruling out any policy that would rely on containment as an option in response to the Iranian nuclear threat.” The implication was that containment is a tepid and passive policy. But it was not such during the 45 years the United States contained the Soviet Union. And containment can involve much more than mere deterrence of Iran, against which the United States has already waged cyber warfare.

Pollack believes that were it not for Israel “repeatedly sounding the alarm,” Iran “probably would have crossed the nuclear threshold long ago.” But if a nuclear Iran is for Israel unthinkable because it is uncontainable, Israel’s only self-reliant recourse – a nuclear attack on Iran’s nuclear infrastructure – is unthinkable. And, Pollack thinks, unnecessary. The existence of Israel’s nuclear arsenal is a sufficient deterrent: The Iranian leadership is “aggressive, anti-American, anti-status quo, anti-Semitic, duplicitous, and murderous, but it is not irrational, and overall, it is not imprudent.”

There will be no constitutional impropriety if Congress recoils against the easing of sanctions and votes to impose even stiffer ones on Iran. The president has primary but not exclusive responsibility for foreign policy. It is time for a debate about the role of sanctions in a containment policy whose ultimate objective is regime change. For many decades prior to 1989, humanity was haunted by the possibility that facets of modernity – bureaucracy and propaganda technologies – could produce permanent tyrannies impervious to change. (See Hannah Arendt’s “The Origins of Totalitarianism.”) In “Nineteen Eighty-Four,” George Orwell wrote, “If you want a picture of the future, imagine a boot stamping on a human face – for ever.” Since 1989, however, tyrannies seem more brittle. And Pollack believes “the basic ingredients of regime change exist in Iran,” which “today is a land of labor protests and political demonstrations.”

Pollack may be too sanguine when he says that, since the brutal smashing of the Green Revolution of June 2009, “the Islamic Republic has been delegitimized and is starting to hollow out.” His fear is that even massive U.S. air strikes would only delay the danger that provoked them, and thus might “prove to be nothing more than a prelude to invasion, as they were in Iraq and almost were in Kosovo.”

The logic of nuclear deterrence has not yet failed in the 64 years since the world acquired its second nuclear power. This logic does not guarantee certainty, but, says Pollack, “the small residual doubt cannot be allowed to be determinative.” His basic point is: “Our choices are awful, but choose we must.” Containment is the least awful response to Iran’s coming nuclear capability.

© 2013, Washington Post Writers Group