The mushroom cloud of the first test of a hydrogen bomb, “Ivy Mike,” as photographed on Enewetak, an atoll in the Pacific Ocean, in 1952, by a member of the U.S. Air Force’s Lookout Mountain 1352d Photographic Squadron. (DSWA-DASIAC via Reuters)

What would happen if a President Donald Trump tore up the Iran nuclear deal?

The presumptive Republican presidential nominee has said he would do that, calling it “disastrous.” A tougher negotiator, he has said, could get more concessions from Iran.

Iran is listening. On his official website, Ayatollah Ali Khamenei, Iran’s supreme leader, wrote that if the United States “tear[s] up the agreement, [Iran] will light it on fire.”

But is Trump right? Could someone willing to walk away from the bargaining table force Iran to accept terms more favorable to the United States? Or is Trump merely encouraging Iran to work secretly toward nuclear weapons, believing that no U.S. administration could guarantee that its successors would consider the deal binding — and thereby making any deal all but impossible to seal?

The logic behind nuclear agreements is a simple quid pro quo

A potential proliferator like Iran agrees to pause or rewind its nuclear program, while opponents like the United States reduce hostilities, deliver inducements, or do both. In theory, both sides win.

With the Iran nuclear deal, Tehran receives an end to sanctions; more short-term security due to reduced hostilities and a lower chance of a preemptive strike on its facilities; and the ability to shift the funds being spent on developing nuclear weapons to more productive programs.

Meanwhile, the United States halts a shift in the military balance of power that Tehran would enjoy should it successfully proliferate. Stopping this is good for the United States: Opponents of nuclear-armed states more frequently back down in military crises, and Iran could have leveraged a nuclear arsenal to achieve more of its policy goals. Even better, the deal came at a relatively low cost to Washington: primarily, the reduction of sanctions and the release of seized Iranian assets.

Furthermore, my research suggests, under the right conditions, a country like Iran has the incentive to comply with such agreements over the long term. Potential nuclear states might at first be tempted to enjoy the short-term benefits of being thought to comply with the agreement, while secretly developing nuclear weapons. Then they can eventually reap the security rewards of a completed bomb. Hence the Iran deal (and similar nonproliferation deals) includes strict verification measures.

In fact, if such a deal is structured right, the potential proliferator faces steep costs for violating its terms and many benefits for complying. That way, continuing the program isn’t worth the risk.

But that’s true only if the potential proliferator can count on future rewards. There’s no incentive to uphold an agreement if rivals might capriciously cut concessions, restore sanctions, or otherwise skip out on their end of the bargain.

That’s why, in an October 2015 open letter to Iranian President Hassan Rouhani, Khamenei stated that “new sanctions on any level with any excuse … will be considered a breach” of the agreement — and Iran would restart its nuclear program.

And that’s why Trump’s threat to tear up the agreement and renegotiate is a double-edged sword. Suppose Iran calculates that it is likely to be forced back to the negotiating table, either now or sometime in the future. That would be a reason to try harder now to develop a weapon — so that it’s holding a better negotiating hand when that time comes. The benefits of compliance may no longer outweigh the costs of developing nuclear weapons.

And if Iran does so, that would be a loss for just about everyone else. The United States would have to respond to a more complicated and dangerous new world in the volatile Middle East. Hawkish U.S. politicians would fail at their long-term goal of preventing Iran from becoming a nuclear power.

But both sides have to keep their commitments or it doesn’t work

Policymakers in Washington have been worrying about whether Iran will comply with the deal. But commitment takes two. Noncompliance on either end can sabotage the agreement on the other. Tehran now finds the deal attractive because of the rewards: the economic benefits of trade and the satisfaction of reentering the community of nations.

But if Tehran expects to be punished no matter what, then why would it comply in the first place?

Washington will never be able to eradicate Iran’s nuclear knowledge. Any threat to renegotiate will bring similarly bellicose responses from Tehran. Threatening to tear up the existing nuclear deal may result in a nuclear Iran.

 

William Spaniel is a Stanton nuclear security postdoctoral fellow at the Center for International Security and Cooperation at Stanford University and, in September, will be an assistant professor in the department of political science at the University of Pittsburgh.