It was so shut. Had only one missile or drone gotten by and killed lots of Israelis, American officers feared, the area may have gone up in flames.

So when Israeli and U.S. forces, with assist from Arab allies, managed a near-perfect protection towards final weekend’s aerial barrage from Iran, it represented not solely a rare army and diplomatic feat but additionally a serious victory for President Biden’s effort to go off escalation of the battle within the Center East.

Mr. Biden and his crew hoped that the developments over the weekend may give all three main actors sufficient to assert victory and stroll away. Iran may declare vindication for taking aggressive motion in response to the Israeli strike that killed some of its prime army officers. Israel confirmed the world that its army is simply too daunting to problem and that Iran is impotent towards it. And the USA stored the area from erupting for an additional day.

It might not work out that approach, nonetheless. Quite than pocketing the win, such because it was, Israeli officers mentioned on Monday that they’d reply — with out saying when or precisely how — and Mr. Biden’s advisers had been bracing to see what that may entail.

A less-visible cyberattack or a pointed however restricted army motion may fulfill Israel’s want to re-establish deterrence with out upsetting Iran into firing again once more. A extra intensive and in-their-face assault on Iranian soil, alternatively, may immediate Tehran to mount a counterattack, and out of the blue the battle may explode right into a sustained and more and more harmful battle.

“This weekend we saw Biden at his best,” mentioned Laura Blumenfeld, a Center East analyst on the Johns Hopkins Faculty for Superior Worldwide Research and a former State Division coverage 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.”

However, she added, the fact is that the Israel Protection Forces will inevitably reply. “Turning the other cheek is not in the I.D.F. playbook,” she mentioned. “A simple ‘don’t’ won’t work. Israel’s response is not a question of if, but when and how. You can’t get around Middle East math — one grave, opposite one grave.”

Some hawkish analysts mentioned that Mr. Biden was fascinated with all of it flawed. His effort to keep away from escalation could set off one as an alternative, they argued, as a result of Iran and different enemies have been emboldened by more and more public disagreements between Washington and Jerusalem over Israel’s conduct of the battle towards Hamas in Gaza.

“This perception of separation may have been a factor in Iran taking the unprecedented step of attacking Israel directly,” mentioned Ray Takeyh, a senior fellow on the Council on International Relations.

It was not sufficient to shoot down Iranian missiles, he added.

“Stopping the attacks after they launch is not the same as deterring them from being launched,” he mentioned. “If Biden’s team once more seeks to carve out a space between itself and Israel, then it will invite further conflict.”

The profitable protection of Israel was the consequence of 10 days of intense diplomacy and army coordination by the Biden administration and years of safety relationships constructed up by a number of administrations all through the area. After it grew to become clear that Iran was planning to strike Israel for the primary time after many years of shadow battle, American officers scrambled to activate, for the primary time, regional air protection plans which were within the works for years.

American army officers labored carefully with Israeli counterparts to map out a scheme to take down incoming missiles and drones, coordinated with British and French forces within the area, and organized with Arab allies to offer intelligence and monitoring knowledge and allow use of their airspace.

Jordan, which has been extremely vital of Israel’s battle in Gaza, nonetheless shot down Iranian drones crossing over its territory towards Israel. An American Patriot battery primarily based in Iraq shot down an Iranian ballistic missile crossing by Iraqi airspace.

In some methods, the bigger cooperation towards Iran is the outgrowth of the altering politics of the area, as exemplified by the Abraham Accords sealed beneath President Donald J. Trump, by which Arab states just like the United Arab Emirates and Bahrain established regular diplomatic relations with Israel for the primary time. The Biden administration has been making an attempt to attract Saudi Arabia into the accords, and whereas no deal has been reached, the sheikhs in Riyadh have been able to construct ties with Israel partly out of shared animosity towards Iran.

The interception of practically each one of greater than 300 missiles and drones with none fatalities in Israel and even main bodily injury felt like validation for individuals who have labored on erecting an internet of safety preparations within the area.

John F. Kirby, a nationwide safety spokesman for the White Home, referred to as it a “spectacular” success. “That’s the upshot here,” he mentioned at a briefing on Monday. “A stronger Israel, a weaker Iran, a more unified alliance and partners. That was not Iran’s intent when it launched this attack on Saturday night, not even close. Again, they failed. They failed utterly.”

Mr. Kirby disputed hypothesis that Iran didn’t actually intend to do injury as a result of it telegraphed its coming assault for greater than every week, and he denied studies that Tehran had even handed alongside messages by intermediaries giving particulars about time and targets. He scoffed on the suggestion that greater than 300 missiles and drones amounted to only a face-saving train.

“Maybe they want to make it appear like this was some sort of small pinprick of an attack that they never meant to succeed,” he mentioned. “You can’t throw that much metal in the air, which they did, in the time frame in which they did it, and convince anybody realistically that you weren’t trying to cause casualties and that you weren’t trying to cause damage. They absolutely were.”

Mr. Biden himself has mentioned little publicly in regards to the strike. “Together with our partners, we defeated that attack,” he mentioned on Monday in his first public look because the strike, a White Home assembly with Prime Minister Mohammed Shia al-Sudani of Iraq. “The United States is committed to Israel’s security.”

Mr. Sudani, whose nation maintains a fragile steadiness between the USA and Iran, mentioned he favored efforts to cease “the expansion of the area of conflict, especially the latest development.”

However he additionally used the chance to press Mr. Biden about his help for Israel’s battle in Gaza. “We’re actually very eager about stopping this war, which claimed the life of thousands of civilians — women and children,” Mr. Sudani mentioned.

The flare-up with Iran has diverted consideration from the Gaza battle on the very second when Mr. Biden had begun turning up the stress on Prime Minister Benjamin Netanyahu to do extra to ease civilian struggling.

Shibley Telhami, a Center East scholar on the College of Maryland, mentioned Mr. Netanyahu had an curiosity in prolonging the dispute with Tehran, “both as a distraction from the horrors of Gaza and as a way of changing the subject to an issue where he is more likely to get sympathy in the U.S. and the West.”

Mr. Telhami mentioned the success over the weekend did little to undo “the damage of Biden’s strategic failure” in stopping the disaster in Gaza. “It shouldn’t take our attention away from this bigger strategic failure, whose costs have been immense and still unfolding,” he mentioned.

Nonetheless, Natan Sachs, director of the Middle for Center East Coverage on the Brookings Establishment in Washington, mentioned it was no small matter to avert a bigger regional battle, at the very least for now.

“Biden deserves big credit,” he mentioned. On the identical time, he added, it could fade quick. “We’re still on the edge because the circumstances are extraordinary and the crisis could escalate any day.”