Don’t Let Iran Cross the Nuclear Threshold

President Trump’s deadline for a deal to dismantle Iran’s nuclear program is fast approaching. Without a credible military threat, if Tehran fails to comply, the regime will confidently wait out the United States, call the president’s bluff and angle for a dangerously one-sided agreement. The odds of preventing a nuclear Iran peacefully have always been exceedingly low.

The regime has zero intention to repeat Moammar Gaddhafi’s fate after the Libyan dictator relinquished his weapons of mass destruction. Absent an acceptable settlement in the near term, Israel appears intent to strike while the regime’s defenses remain down rather than wait until the last minute to try to catch the final turn of the screw on a bomb. By itself, “maximum pressure” from U.S. sanctions cannot sway a regime with so much invested in its atomic venture and so little regard for its own people.

Recently, Iran’s president essentially dared the United States to walk away from talks and pile on more sanctions. Instead, realistic prospects of overwhelming force can really focus minds in Tehran. Earlier this year, Iran’s supreme leader, Ayatollah Ali Khamenei, overcame his profound reluctance to engage with Washington once he feared serious conflict, including strikes on Iran’s nuclear facilities, as the only alternative. His decision was helped by Israeli strikes that devastated many of the regime’s best defenses and retaliatory capabilities late last year. Yet Iran also knows all too well how to offset its weaknesses by exploiting negotiations.

As they did with Presidents Obama and Biden, Tehran’s diplomats are slow-rolling talks, playing for precious time to move closer to a bomb, rebuild the regime’s arsenals, erode U.S. leverage by running out the clock on Mr. Trump’s deadline and ultimately forestall military action. It’s working. In a major story that broke on the eve of talks, Mr. Trump told Israeli officials he would not support military action and risk disrupting his pursuit of a deal. He reiterated that message late last month. With the United States and Israel at odds, talks are headed in the wrong direction as Iran defiantly rejects any hint of dismantlement.

A report from the Jewish Institute for National Security of America explains why the United States has every interest in maximizing the credibility of this threat and minimizing open disagreements over military options. It offers the best chance, albeit small, of coercing Iran to demolish its atomic infrastructure before Mr. Trump’s 60-day ultimatum comes due. If Tehran refuses, U.S.-Israeli cooperation will be the only viable option left.

Sticking with diplomacy would either produce a repeat of Mr. Obama’s untenable Joint Comprehensive Plan of Action nuclear deal or risk triggering an Israeli strike that catches America off guard and deals merely limited damage to Iran’s nuclear weapons infrastructure. Ideally, the United States would be a full partner or, at minimum, provide Israel with essential support in a strike and its aftermath. Equally important, there is a shared interest in deterring severe Iranian reprisals against Israel, U.S. regional bases and Gulf partners. The United States should warn Iran that any such retaliation would put the regime itself at direct risk.

Tehran must be under no illusion that the existence of the 46-year-old Islamic republic could be in jeopardy. Washington and Jerusalem also must make clear their readiness to prevent Iran from trying to reconstitute its nuclear weapons program post-strike. This entails truly maximum pressure — economic, diplomatic, covert and, when necessary, military — as long as this regime persists. Any operation against Iran’s resilient and furtive nuclear activities must be understood as a long-term campaign, not a one-off strike.

Military action certainly has unknowns that should not be minimized, but the risk of inaction is greater. The United States cannot permit Iran to become a nuclear weapons power, threaten the existence of Israel and other U.S. partners, trigger a Middle East arms race and evict the United States from the region. The longer talks drag on, the more likely Iran is to achieve these objectives with or without a deal.