A Diplomatic Victory of Uncertain Staying Power

It was so close. Had just one missile or drone gotten through and killed a lot of Israelis, American officials feared, the region could have gone up in flames.

So when Israeli and U.S. forces, with help from Arab allies, managed a near-perfect defense against last weekend’s aerial barrage from Iran, it represented not only an extraordinary military and diplomatic feat but also a major victory for President Biden’s effort to head off escalation of the war in the Middle East.

Mr. Biden and his team hoped that the developments over the weekend could give all three major actors enough to claim victory and walk away. Iran could claim vindication for taking aggressive action in response to the Israeli strike that killed some of its top military officers. Israel showed the world that its military is too formidable to challenge and that Iran is impotent against it. And the United States kept the region from erupting for another day.

It may not work out that way, however. Rather than pocketing the win, such as it was, Israeli officials said on Monday that they would respond — without saying when or exactly how — and Mr. Biden’s advisers were bracing to see what that might entail.

A less-visible cyberattack or a pointed but limited military action might satisfy Israel’s desire to re-establish deterrence without provoking Iran into firing back again. A more extensive and in-their-face attack on Iranian soil, on the other hand, could prompt Tehran to mount a counterattack, and suddenly the conflict could explode into a sustained and increasingly dangerous war.

“This weekend we saw Biden at his best,” said Laura Blumenfeld, a Middle East analyst at the Johns Hopkins School for Advanced International Studies and a former State Department policy adviser. “The U.S.-led aerial display with European and Arab regional partners played like an action movie trailer for a new Middle East air defense alliance.”