In the immediate aftermath of Tehran’s spectacular, but almost entirely thwarted, attack on Israel, it appeared that the Middle East had dodged a bullet. Iran’s barrage of more than 300 drones and missiles enables its leadership to claim vengeance for Israel’s April 1 assassination of seven senior Revolutionary Guards commanders. Israelis, meanwhile, can revel in the extraordinary operational success of the country’s sophisticated air defense systems, reinforced by an impressive array of wingmen from the American, British, French, and Jordanian militaries, who helped ensure that Iran did not hit a single Israeli target.

Washington is certainly hoping that there will now be a lull in the Iranian-Israeli conflict. Six months of grueling war and dire humanitarian conditions in the Gaza Strip have strained U.S. domestic politics and decision-makers’ bandwidth, and so Washington has little appetite to address another crisis. That is why, in the wake of the failed strikes, U.S. President Joe Biden urged the Israelis to “take the win” and “slow things down and think through” any reprisal that might precipitate a wider war in the Middle East.

Unfortunately, Biden’s prudence is not shared by his counterparts in Jerusalem and Tehran. Especially after the October 7 Hamas massacres, Iran’s unprecedented strike on Israeli territory has transformed the confrontation from one taking place mainly in the shadows to an imminent existential peril. As a result, any initial restraint could prove fleeting.

A wider conflict would have a cascade of devastating implications for the region and the world. It would exacerbate violence and displacement across the region, torpedo progress toward Arab-Israeli normalization, generate significant economic disruptions with far-reaching effects. Staving off such a disaster will require that Washington use its unmatched diplomatic and military resources in ways that it has hesitated to deploy so far. It must both push for a pause to the fighting in Gaza—which would deprive Iran of reasons to keep attacking Israel—and seriously threaten Tehran to deter it from further retaliation. Washington may not be happy about taking these measures, but it has no choice. Only the Biden administration, beleaguered as it may be, can head off a catastrophic escalation.

IN THE SHADOWS

Iran has engaged in armed confrontation with Israel for more than 40 years. But it has done so indirectly and covertly. As I laid out in a recent Foreign Affairs essay (“Iran’s Order of Chaos”), Tehran has invested in and relied on proxy militia groups, which expand the regime’s influence while still insulating its leaders from risk. Iran, for example, collaborated with Hezbollah in 1992 to carry out a bombing of the Israeli embassy in Buenos Aires that killed 22 people, but Iranian forces did not take part in the attack itself. In recent years, Tehran has funded, trained, and sent advanced weaponry (and knowledge about how to produce it) to a panoply of terrorist organizations that have killed Israelis at home and around the world, including Hezbollah, the Houthis in Yemen, Shia militias Iraq and Syria militias, as well as Palestinian Islamic Jihad and Hamas. Yet until last week, its own troops never struck Israel or Israelis.

Over time, the violence became a two-way street, with Israel mounting increasingly inventive efforts to preempt and retaliate against aggression from Iran and its proxies. Analysts, officials, and news organizations believe that Israel is responsible for the assassinations of at least six Iranian nuclear scientists (building on its long history of covertly killing terrorists). This includes the architect of Iran’s nuclear program, who was killed in an extraordinary 2020 operation involving a remote-controlled weapon. Israel has also conducted acts of sabotage and cyberattacks to slow Iran’s nuclear advancement. It even absconded with the official archives of Iran’s nuclear program. But Israel has never acknowledged its part in any of these measures. The country has been more open about its long-term military campaign to degrade and disrupt Iranian capabilities in Syria, including its airstrikes on Iranian weapons shipments and military positions. Yet Israel has never overtly attacked Iranian territory, either.

The bloodshed, in other words, had a clearly defined limit. Both states observed an unstated injunction against any frontal assault on their respective home turfs, which would threaten to turn their simmering conflict into an all-out war that could engulf the broader region. Such a war would precipitate even greater dangers: for Israel, an Iranian nuclear weapon, for Tehran, U.S. military intervention. Multiple Israeli leaders have mulled taking military action against Iran’s steadily expanding nuclear infrastructure, as they did with Iraq in 1981 and Syria in 2007, but they ultimately deferred in favor of other tools. Meanwhile, Tehran’s experience during its devastating eight-year war with Iraq conditioned a hard-won realism about the prospects of easy victory in a battle against an adversary with superior power. As a result, the regime’s wily strategists understood that their advantage lay in using asymmetric capabilities, including their proxies.

WISHFUL THINKING

To some observers, Iran’s attack is just a blip in this long-running pattern. In this interpretation, the strikes may have been merely symbolic or signaling. Tehran’s heavy-handed efforts to preview its plans for neighboring governments were intended to ensure that its slow-moving drones would be neutralized en route and that the overall impact of the strike would be negligible. After all, early analysis showed that only five of the 120 ballistic missiles fired from Iran actually crossed into Israeli territory, and that none of the 170 drones or 30 cruise missiles did. Iranian officials also issued a statement declaring an end to the clash before it was even over.

This rationalization is reasonable in the wake of Iran’s dramatic failure, but it does not hold up to scrutiny. Having held back for more than four decades, Tehran must have appreciated the implications of its decision to defy one of the few taboos in the enduring conflict with Israel. It also understood the copious alternatives available to them to even the score, including attacking via proxy forces.

An intentionally ineffectual Iranian attack would also hardly serve as a compelling deterrent. The failure to hit a single target might persuade Tehran’s adversaries that the regime is a paper tiger. Instead, the scale, scope, and complexity of the strikes were so considerable—larger than Russia’s biggest aerial assaults on Ukraine—that they seem to have had a greater aim: overwhelming Israel’s vaunted aerial defense systems. On that basis, Iranian leaders had to anticipate at least some Israeli casualties. From experience, they would understand that this would precipitate reprisal attacks. And yet they went forward nonetheless, in defiance of specific admonitions from Biden.

Iran’s readiness to escalate betrays a shift that has taken place gradually over the past decade, as Iran’s original generation of revolutionary leaders has given way to a narrower and more hard-line faction. The pragmatic self-interest that drove historic compromises by previous Iranian leaders, evident in former Iranian President Ali Akbar Hashemi Rafsanjani’s push to end the war with Iraq in 1988 and former President Hassan Rouhani’s determination to achieve a nuclear truce, has dissipated. Instead, foreign policy decisions are increasingly in the hands of battle-hardened veterans of Iran’s regional adventures. The result is a new assertiveness, even recklessness, underpinned by an affinity with China and Russia that has displaced any interest in rehabilitating its relationships with the West. As a result, the regime may be inclined to attack Israel again in an effort to compensate for the embarrassing result of its most recent performance.

PRIMED TO FIGHT

Iran is not alone in being pushed toward escalation. Tehran’s attack ups the ante for an Israeli leadership that is already primed for action, as a result of past precedent and Israeli security doctrine. The country’s small size, its unique place as the homeland for the Jewish people, and the weight of historical memory have inspired a commitment to military self-reliance as well as a determination to ensure no adversary can act on threats to Israel’s existence. The government is also under substantial pressure to respond given its failure to foresee or mount an effective initial defense against Hamas’s shock attack. The country is still reeling from the terror and trauma of October 7, as well as the continued hostage crisis, and so few of its citizens are in the mood to hold back.

There are, of course, contradictory precedents, such as the 1991 missile attacks by Saddam Hussein—which Israel ultimately left unanswered. There are also countervailing pressures. The Iranian attacks have reinvigorated strong public solidarity with Israel in Europe. They pushed Israel’s regional partners, which have deplored the humanitarian crisis created by Israel’s Gaza campaign, to participate in its defense. If Israel responded, it might lose this goodwill. A show of restraint, by contrast, could bear fruit. It might help Israel build a robust strategic coalition and restore some momentum to its pre–October 7 plans to normalize relations with Saudi Arabia. Perhaps that is why Benny Gantz, a centrist politician who is a member of the country’s war cabinet, has demurred on the question of whether Israel should retaliate and advocated for using this opportunity to strike new deals with Arab states.

But the country’s all-out war in Gaza leaves no doubt about its leadership’s determination to eliminate its adversaries at almost any price. Casualties or not, the specter of future Iranian drone and missile barrages will harden Israel’s desire to degrade or eliminate the threat posed by Iran, its proxies, and its nuclear program. Those attacks may not come immediately or in the following weeks and months. But the baseline of Iranian-Israeli antagonism will remain elevated, the threshold for escalation lower, and the odds of miscalculation harrowingly high.

AMERICA’S CONUNDRUM

This new normal is especially unwelcome for the Biden administration. Since taking office, the president has tried hard to extricate the United States from the Middle East’s conflicts. He has worked to complete Washington’s long-attempted pivot to Asia, and he has focused heavily on helping Ukraine defend itself from Russia’s invasion. He rushed to Israel’s defense after October 7, but the White House has pushed hard for an end to the war in Gaza over the last several months. Biden certainly does not want to have to contend with even more turmoil in the region, especially in the midst of a fraught U.S. election, in which the politics of Middle East policy have featured in dramatic ways.

But even for an administration prepared to ruthlessly prioritize American national security interests, a spiraling Iranian-Israeli conflict creates too many severe human, strategic, and economic risks to ignore. Like it or not, Washington is going to have embrace the thankless task of stabilizing the Middle East through energetic diplomacy and by projecting power.

Biden can start by amplifying his warning to Tehran and making clear that future attempts to attack Israel will be met with U.S. reprisals. He should make clear that Washington will respond to attacks on its partners and build on the success of foiling Iran’s strikes to deepen regional security integration. In addition, Biden should invest the copious political capital he has accumulated with Israel since October 7 to meaningfully shift the country’s approach to the war in Gaza away from indifference, or worse, toward the lives and futures of Palestinian civilians. Instead, Israeli leaders must develop a strategy that is designed not just to eradicate Hamas but to ensure good governance and security in the aftermath. It is time for Israel and the United States to recognize that the humanitarian crisis and governance vacuum in the enclave undermines Israel’s legitimate effort to remove Hamas from power and that the crisis provides an opening for Tehran.

A full-force effort by Biden to pause the war could well succeed. When Biden has used U.S. leverage with Israel, as he did recently after an Israeli strike killed aid workers, he has achieved real progress. If the president redoubled his efforts, it could enable an infusion of food and other desperately needed relief to Palestinians and create space to hold talks aimed at stabilizing tensions with Hezbollah along Israel’s northern border. Doing so will begin to limit Iran’s room for maneuver. Biden should also press Israel to calibrate any retaliation to avoid precipitating further Iranian escalation. Israel can then again work toward deepening its security cooperation with its neighbors—which, as April 14 showed, is critical to the state’s safety.

None of these steps will conclusively eliminate the threat posed by the Iranian regime to its neighbors, including Israel, and to the world. Ultimately, the fate of that regime remains in the hands of the Iranian people. But Washington can help deter Tehran and address the instability that gives the Islamic Republic such dangerous opportunities. Even a cold-blooded cost-benefit analysis justifies an investment, once again, of American blood, treasure, and leadership attention. Like Beijing and Moscow (and often in concert with them), Tehran is seeking to reshape the regional order to its advantage. Only the United States can lead an effort to ensure that it does not prevail.