Israel struck decisively Friday at what its leaders have called “the head of the snake” - assassinating senior Iranian military commanders and scientists who helped direct Tehran’s nuclear program and proxy forces, along with a range of other military targets. In its first hours, this appeared to be conceived as a “decapitation” strike, much like Israel’s devastating attack last fall against Hezbollah in Lebanon.

But this snake is hard to kill. Especially when President Donald Trump, the leader of Israel’s closest ally, has been playing the role of snake charmer. “I gave Iran chance after chance to make a deal,” he said Friday, warning Iranian leaders that there was “much more to come” from Israel - and then in the same social media post imploring them to “make a deal, before there is nothing left, and save what was once known as the Iranian Empire.”

Trump’s diplomatic opening to Iran, leveraged by Israel’s overwhelming military force, is among the most ambitious moves of his presidency. But given the covert tools Iran has at its disposal for retaliation - especially through its links to al-Qaeda operatives in Yemen and Afghanistan - Trump should remind himself that he needs to move with care. Misjudging Iran could have catastrophic consequences.

Israel hunkered down Friday for Iranian retaliatory attacks, which began with a 100-drone assault. The response escalated just after 9 p.m. Israeli time, with what reporters on the scene said were some 100 Iranian ballistic missiles.

Israeli Prime Minister Benjamin Netanyahu must hope that the assault that began Friday, and could last days, will be the conclusive campaign in the war that began when Iranian-backed Hamas terrorists surged across the Gaza fence on Oct. 7, 2023. It’s likely Netanyahu chose to act now because he believed Iran would never again be so vulnerable - and perhaps also because he wanted to derail a Trump diplomatic bid that he mistrusts.

The wild card in this conflict is that the United States, Israel’s superpower ally, is for now standing on the sidelines. Rarely has a U.S. secretary of state made such a cold-blooded statement of nonalignment as Marco Rubio’s in the opening hours of the attack: “We are not involved in strikes against Iran and our top priority is protecting American forces in the region.” As Iranian retaliation escalates, it’s hard to imagine Trump resisting what will be growing political pressure to intervene on Israel’s behalf, and by late Friday, Axios reported that the U.S. military was assisting Israel in unspecified ways.

Trump and Netanyahu diverged soon after Trump was inaugurated. Netanyahu went to Washington in February hoping to get Trump’s backing for a bombing campaign against Iranian nuclear facilities. But Trump balked, and in an Oval Office meeting in April, with Netanyahu sitting uncomfortably next to him, Trump announced that he was opening negotiations with Tehran.

The result has been a three-way game of chicken in recent weeks. Israel seemed threatened as much by Trump’s diplomacy as Iran’s missiles. Netanyahu decided this week that he couldn’t wait any longer.

Israel mounted a brilliant, stealthy assault Friday. Using pre-positioned drones and other weapons, it struck precisely in the predawn darkness at the homes of Mohammed Bagheri, the Iranian military chief of staff, and three other top generals. Israel also reportedly assassinated two top nuclear scientists. Video footage from Tehran confirmed the precision of the attacks - showing one floor of an apartment building hit, for example, but not the others.

Mossad has created a drone base in the heart of Tehran, said Amit Segal, a well-sourced Israeli journalist. He noted that Israel placed these in-country weapons next to antiaircraft complexes and on special roving vehicles so that they could disable Iranian defenses jut as the assault began. Israel reportedly used more than 200 fighter jets, striking in several waves. By Friday, Iran appeared as vulnerable as Gaza to Israeli air attack.

Until last fall, Iran’s main deterrent force had been Hezbollah’s enormous rocket arsenal in Lebanon. That has now been largely neutered by Israeli strikes. But Iran has other means to hit back. One that has received little attention is its relationship with al-Qaeda affiliates. The al-Qaeda affiliate in Yemen may pose a special danger. It’s headed by Saad bin Atef al-Awlaki, who posted a chilling video this month threatening U.S. officials. “Go after the scum of the earth and its greatest criminals,” he urged his followers, naming Trump, Vice President JD Vance, Defense Secretary Pete Hegseth and former DOGE chief Elon Musk. According to the Jerusalem Post, Awlaki urged Muslims in Europe and America to make sure there is “not a single safe place” for Jews.

Israel’s tactical mastery is unquestioned. But in this latest assault on Iran - as in earlier campaigns in Gaza, Lebanon, Syria and Yemen - Israel appears to have given relatively little thought to “the day after.” Does Israel seek regime change in Iran, to permanently bend Iran away from its revolutionary course? Or is this a strike that will neuter the Iranian nuclear threat for a few more years but set up a future conflagration?

As many decades have taught the United States and Israel both, conflicts with Iran are easy to start and hard to end.

David Ignatius is a Washington Post columnist