The Best Arguments for an Iran Deal

In formal rhetoric, prolepsis means the anticipation of possible objections to an argument for the sake of answering them. So let’s be proleptic about the Iranian nuclear deal, whose apologists are already trotting out excuses for this historic diplomatic debacle.

The heroic case. Sure, Supreme Leader Ali Khamenei is an irascible and violent revolutionary bent on imposing a dark ideology on his people and his neighborhood. Much the same could be said of Mao Zedong when Henry Kissinger paid him a visit in 1971—a diplomatic gamble that paid spectacular dividends as China became a de facto U.S. ally in the Cold War and opened up to the world under Deng Xiaoping.

But the hope that Iran is the new China fails a few tests. Mao faced an overwhelming external threat from the Soviet Union. Iran faces no such threat and is winning most of its foreign proxy wars. Beijing ratcheted down tensions with Washington with friendly table-tennis matches. Tehran ratchets them up by locking up American citizens and seizing cargo ships in the Strait of Hormuz. Deng Xiaoping believed that to get rich is glorious. Iranian President Hasan Rouhani, a supposed reformer, spent last Friday marching prominently in the regime’s yearly “Death to America, Death to Israel” parade.

If there is evidence of an Iranian trend toward moderation it behooves proponents of a deal to show it.

The transactional case. OK, so Iran hasn’t really moderated its belligerent behavior, much less its antediluvian worldview. And a deal won’t mean we won’t still have to oppose Iran on other battlefields, whether it’s Yemen or Syria or Gaza. But that doesn’t matter, because a nuclear deal is nothing more than a calculated swap. Iran puts its nuclear ambitions into cold storage for a decade. In exchange, it comes in from the cold economically and diplomatically. Within circumscribed parameters, everyone can be a winner.

But a transaction requires some degree of trust. Since we can’t trust Iran we need an airtight system of monitoring and verification. Will the nuclear deal provide that? John Kerry will swear that it will, but as recently as January Czech officials blocked a covert $61 million purchase by Iran of “dual-use” nuclear technologies. A month before that, the U.S. found evidence that Iran had gone on an illicit “shopping spree” for its plutonium plant in Arak. That’s what we know. What do we not know?

Also, how does a nuclear deal not wind up being Iran’s ultimate hostage in dictating terms for America’s broader Mideast policy? Will the administration risk its precious nuclear deal if Iran threatens to break it every time the two countries are at loggerheads over regional crises in Yemen or Syria? The North Koreans already mastered the art of selling their nuclear compliance for one concession after another—and they still got the bomb.

The defeatist case. All right: So the Iran deal is full of holes. Maybe it won’t work. Got any better ideas? Sanctions weren’t about to stop a determined regime, and we couldn’t have enforced them for much longer. Nobody wants to go to war to stop an Iranian bomb, not the American public and not even the Israelis. And conservatives, of all people, should know that foreign policy often amounts to a choice between evils. The best case for a nuclear deal is that it is the lesser evil.

Then again, serious sanctions were only imposed on Iran in November 2011. They cut the country’s oil exports by half, shut off its banking system from the rest of the world, sent the rial into free fall and caused the inflation rate to soar to 60%. By October 2013 Iran was six months away from a severe balance-of-payments crisis, according to estimates by the Foundation for Defense of Democracies. And that was only the first turn of the economic screw: Iran’s permitted oil exports could have been cut further; additional sanctions could have been imposed on the “charitable” foundations controlled by Iran’s political, military and clerical elite. Instead of turning the screw, Mr. Obama relieved the pressure the next month by signing on to the interim agreement now in force.

It’s true that nobody wants war. But a deal that gives Iran the right to enrich unlimited quantities of uranium after a decade or so would leave a future president no option other than war to stop Iran from building dozens of bombs. And a deal that does nothing to stop Iran’s development of ballistic missiles would allow them to put one of those bombs atop one of those missiles.

Good luck. Americans are a lucky people—lucky in our geography, our founders and the immigrants we attract to our shores. So lucky that Bismarck supposedly once said “there is a special providence for drunkards, fools, and the United States of America.”

Maybe we’ll get lucky again. Maybe Iran will change for the better after Mr. Khamenei passes from the scene. Maybe international monitors will succeed with Iran where they failed with North Korea. Maybe John Kerry is the world’s best negotiator, and this deal was the best we could do.

Or maybe we won’t be lucky. Maybe there’s no special providence for nations drunk on hope, led by fools.

Write to bstephens@wsj.com.