Iran nuke deal should end threat, not postpone it

Judging by public statements, prospects for a new deal to contain Iran’s nuclear program may be improving. A top adviser to Supreme Leader Ayatollah Ali Khamenei has affirmed the regime is willing to dispose of its stockpiles of highly enriched uranium, restrict itself to a purely civilian program and commit to never developing a bomb. While the US should accept nothing less, a truly effective agreement will require more.

Negotiators have now held four rounds of talks. That’s encouraging, but it also suggests the US has given up on the broader “grand bargain” one would’ve hoped to see. While at certain points American officials have spoken of addressing all of Iran’s malign activities — including its ballistic-missile buildup and support for regional terrorist groups — and of entirely “dismantling” its nuclear program, it is unlikely Iranian negotiators would still be at the table if such issues were under discussion. Talks instead seem to be focused on the same challenge that animated the 2015 Joint Comprehensive Plan of Action: how to ensure Iran’s enrichment activities don’t lead to a nuclear weapon.

The trouble is that the Iranian nuclear program looks very different now than it did a decade ago. At the time, the restrictions imposed on the number of centrifuges Iran could deploy and levels to which it could enrich gave the US and its allies confidence that the regime would need at least a year to “break out” and produce enough weapons-grade uranium for a bomb. That should’ve guaranteed sufficient time to mount a forceful response.

Since then, the regime has built and installed thousands of more sophisticated centrifuges and gained valuable experience running them. Using current stockpiles of fissile material, US officials have said, it could produce enough highly enriched uranium for a weapon in less than a week. Even if it started from scratch, its cascades of advanced centrifuges could likely accomplish the task in less than five months.

Such powerful capabilities aren’t needed for the civilian nuclear program Iranian leaders claim they want. Any new deal, therefore, ought to ensure that all advanced centrifuges are destroyed or removed from the country. Even the number of first-generation devices allowed should be strictly limited, so Iran doesn’t try to make up in quantity what it’s losing in quality.

Given the regime’s record, additional reassurances will be needed. Iranian officials must resolve lingering questions from the International Atomic Energy Agency about their past efforts to develop a nuclear weapon. They should be pressed to accept intrusive monitoring by American or European inspectors, in addition to the IAEA, both to demonstrate compliance with any new agreement and to prove they haven’t diverted centrifuges or fissile material to undeclared sites.Finally, the White House shouldn’t repeat the most egregious flaw in the 2015 deal by accepting time limits on Iran’s obligations. Such sunset clauses would simply postpone the threat of an Iranian bomb. Restrictions on enrichment will have to be indefinite or pushed out so far into the future that they might as well be.Iran’s leaders ought to recognize that such concessions are in their own interest. If any new agreement — and, more important for them, any US sanctions relief — is to survive this administration, it will need to be ratified by bipartisan majorities in Congress. That would’ve been a tough sell even if the deal had aimed to dismantle Iran’s nuclear infrastructure, shrink its missile arsenal and cut off support for terrorism. A narrower agreement will need to be even more airtight.

The administration deserves credit for seeking a diplomatic formula that might ease concerns about Iran’s nuclear ambitions. It shouldn’t settle for one that doesn’t.