Amos Yadlin and Avner Golov

“The horrible Iran deal,” President-elect Donald Trump tweeted just before the new year. These words have been largely ignored. They should not be. They indicate that his pledge during the campaign to tear up and renegotiate the nuclear accord with Iran remains viable. To be sure, the Joint Comprehensive Plan of Action, as it is formally called, is highly flawed. But it would be foolhardy and risky for America to scuttle it now.

First of all, it is improbable that Russia, China, Britain, France and Germany — the other five parties to the deal — would agree to jeopardize it. Pulling out would isolate the U.S. from the coalition it successfully created and leave no credible means for stopping Iran from acquiring nuclear weapons, the objective of the deal.

A second reason to keep the deal in place is that during its first seven years, it delivers a period of significant constraints over Iran’s nuclear program along with tight inspections and monitoring. But in the eighth year, 2023, as President Obama has acknowledged, the agreement will gradually allow Iran to build enough nuclear capability to reach almost zero "breakout time" (the time needed to produce enough fissile material to make a bomb).

That makes those first seven years an opportune time to address the deal’s flaws. The United States should put into place partnerships and plans to deter any Iranian effort to race toward nuclear weaponry once the constraints on its nuclear program start waning.

Third, tearing up the deal would create a dangerous void: Washington would be provoking Tehran at a moment when it has no credible leverage to restrain Iran on its own. Because this is an international rather than bilateral deal, so long as Iran complies with it, international sanctions would not be restored and international legitimacy for military action would be weak or withheld entirely.

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Consequently, the incoming Trump administration should revive the two main levers that brought Iran to the negotiations but were partially abandoned by the Obama administration: a credible threat of sanctions that could severely damage the Iranian energy and financial sectors, and a credible surgical military option.

The prevailing impression today is that the U.S. is not willing to seriously challenge any Iranian violations of the agreement as long as Iran does not actually produce nuclear weapons. To restore American deterrence, the new president should make two positions clear:

First, the U.S. is willing to reimpose economic sanctions in the event of Iranian non-compliance.

Second, America will not hesitate to use military force to prevent Iran from dashing for the bomb or from reducing its breakout time to a few months or even weeks after restrictions begin to wane. This red line is crucial to maintaining the deal's main achievement — prolonging Iran’s breakout time to one year — once international restrictions are lifted.

The U.S., working with the other powers and Israel, should also use the deal’s first eight years to counter Iran's non-nuclear misbehavior, which was excluded from the bargain.

To secure implementation of the agreement, the Obama administration signaled its reluctance to halt Iran's attempts to achieve regional hegemony. Trump's public revulsion toward the deal provides him with more latitude in this realm. The new administration should assertively react to attacks on U.S. forces in the region by Iran or its allies, such as the Houthis’ strikes against U.S. Navy ships in October. It should thwart Iran’s military assistance to terror organizations, including Hezbollah, the Houthis in Yemen, and Hamas. And it should enforce United Nations Security Council Resolution 2231, which prohibits Iran from developing a ballistic missile program designed to carry nuclear weapons.

Close cooperation with Israel could strengthen the American position. Israeli intelligence on Iran can assist in detecting Iranian violations, while an Israeli military threat could also persuade Iran not to exploit the flaws in the accord and shorten its distance to a nuclear bomb.

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Therefore, Washington and Jerusalem should formulate a parallel agreement to cope with this challenge, maximizing their joint assets and avoiding public quarrels. They should agree on the appropriate response to potential Iranian violations of the nuclear deal or any crossing of the new American red line. Their plan should provide Jerusalem with the necessary legitimacy and capacity to act as a last resort in coordination with Washington to prevent a nuclear Tehran. It should strengthen deterrent instruments against Iran in anticipation of the lifting of a significant portion of the restrictions on the Iranian nuclear infrastructure. If deterrence and diplomacy fail, this partnership could be the last chance to stop Iran from going nuclear.

By not canceling the agreement outright, Trump would have the opportunity to amend its flaws and create a better strategic reality, while cultivating the requisite tools to stop Iran from going nuclear when the deal ends or if it collapses. Such an approach represents the best alternative to the accord. It is better than negating it, and better than allowing it simply to run its course.

Retired major general Amos Yadlin, former chief of Israeli military intelligence, is executive director of Tel Aviv University’s Institute for National Security Studies. Avner Golov is a research fellow at the institute and Harry S. Truman Scholar at the Fletcher School of Law and Diplomacy, Tufts University.

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