Sometimes, the most crucial test of a powerful country involves not its strength but its judgment. The United States faces just such a test now, as Israel wages a determined campaign against Iran and U.S. President Donald Trump weighs whether to join it.

In recent days, the president has sent mixed signals. “We now have complete and total control of the skies over Iran,” he posted yesterday on Truth Social, pointedly using the first-person plural. In other posts the same day, he mused about killing the supreme leader of Iran and demanded “UNCONDITIONAL SURRENDER!” from the Islamic Republic. After months of talking up the prospects for diplomacy with Iran (and years of bemoaning past American military failures in the Middle East), the famously mercurial Trump seemed to have embraced a more hawkish view.

Earlier today, however, he was more equivocal. “I may do it,” he told reporters. “I may not do it. I mean, nobody knows what I’m going to do.”

If the United States does wind up at war with Iran, it would hardly come as a shock. Enmity toward the Islamic Republic runs deep in Washington—and understandably so. The Iranian regime has held Americans hostage and supported terrorists and insurgents who have killed U.S. service members in Lebanon and Iraq. And a sense of American solidarity with Israel naturally springs from cultural bonds, mutual security interests, and decades of strategic partnership. What is more, this is a fight that makes sense for Israel—a country that is pursuing the kind of strategic clarity that Washington has failed to achieve in its own recent wars. Emerging from the trauma of the October 7 attacks, Israel has sought to eliminate profound threats rather than merely manage them. Israel shattered Hezbollah’s command structure and political standing in Lebanon, helped collapse Bashar al-Assad’s brutal regime in Damascus, and devastated Hamas in Gaza. With Iran’s proxies dismantled and Syrian airspace suddenly open to Israeli jets, the Islamic Republic has become a far more vulnerable adversary. It now faces an Israeli military with formidable intelligence capabilities, superior weaponry, and the political resolve to finish the fight.

Doing otherwise would represent a catastrophic error of judgment on Trump’s part. It would also compromise the “America first” foreign policy that helped bring him to power and that a large majority of Americans support. When he burst onto the political scene in 2015, a significant part of Trump’s appeal rested on his refreshing honesty about Washington’s blunders in the Middle East. At a time when most Republican officials were still trying to say as little as possible about the disastrous Iraq war, Trump loudly echoed the conclusion that the vast majority of Americans had reached years earlier: “Obviously, the war in Iraq was a big, fat mistake,” as he put it in an early GOP primary debate that year.

Now, however, Trump risks making a similarly significant error in the Middle East. His strategic instincts seem to be leading him astray. With any luck, his strong political instincts will kick in, and he will step back from the brink.

ONE THING LEADS TO ANOTHER

The notion that the United States could conduct a limited action against Iran without provoking a desperate and ferocious response reflects a lack of imagination. What begins as a surgical strike on hardened Iranian enrichment facilities buried deep underground at the Fordow site risks spiraling in unpredictable directions. Reprisal attacks would ensue, and all sides would climb the escalation ladder.

Iran would likely retaliate against U.S. troops stationed at exposed and vulnerable bases in Iraq and Syria. It might also hit major American military installations such as the Al Udeid Air Base in Qatar and the U.S. Navy’s Fifth Fleet headquarters in Bahrain. Cyberattacks targeting American energy, financial, and communications infrastructure could follow. Iran could cripple global shipping by lining the Strait of Hormuz with mines and encouraging the Yemen-based Houthi militia to step up its attacks on ships in the Red Sea. In response, the U.S. would almost certainly launch its own retaliatory strikes at a broad array of Iranian military and proxy targets across the region.

As in past American interventions in the Middle East, the conflict could become self-perpetuating. Political off-ramps may evaporate under the inevitable pressure to escalate. What began as a limited strike could transform into a regional war.

Meanwhile, China would probably seek to exploit such a situation to advance its own interests. In recent days, after the Pentagon ordered the USS Nimitz aircraft carrier to relocate from the Indo-Pacific to the Middle East, the Chinese military carried out provocative sea and air patrols in which it shadowed U.S. allies in contested waters. If U.S. forces wind up deployed to the Middle East for a longer period, China could increase its pressure on Taiwan and ramp up its harassment of vessels from the Philippines and Japan. Such provocations would test the resolve of U.S. allies in the region and raise doubts about Washington’s reliability.

MR. MERCURIAL

In addition to posing risks to U.S. interests, American military intervention in Iran could also hurt the very party it intended to help: Israel. For decades, Israeli leaders have made the case that they must defend themselves, by themselves. They have invested heavily in airpower, missile defenses, and cyber-capabilities precisely to ensure that, during a crisis, they are not dependent on an outside power or the whims of their patrons in Washington. American intervention now would render those efforts meaningless, solidifying Israel’s dependence and its junior-partner role in its relationship with Washington.

An American entry could also alter the contours of Israel’s war aims. Even if Trump decides to enter the fight, he may have another change of heart and pressure (or force) Israel to stop short of what Israeli leaders would otherwise consider a satisfactory end state. Trump, after all, is hardly a paragon of consistency. A mere month ago, he demoted his national security adviser, Mike Waltz, by nominating him to serve instead as U.S. ambassador to the United Nations; according to The Washington Post, Trump was irritated that, while he was pursuing a deal with Iran, Waltz had been coordinating closely with Israeli Prime Minister Benjamin Netanyahu on plans to attack. Now, however, Trump himself has apparently leapt into such planning.

Trump might reverse course again, however, especially if he believes the American public—and, in particular, his supporters—are not on board. An Economist/YouGov poll of Americans conducted between June 12 and June 16 asked: “Do you think the U.S. military should get involved in the conflict between Israel and Iran?” Just 16 percent of respondents said yes, while a striking 60 percent said no. Even among Trump voters, who are not necessarily more hawkish but tend to fall in line with the president, only 19 percent supported U.S. military intervention, whereas 53 percent opposed it. Trump is likely keeping a close eye on such numbers—as is Netanyahu.

 

American military intervention in Iran could hurt the very party it intended to help: Israel.

There is also the question of congressional authorization for any American military action, which remains a bedrock constitutional requirement, although one that has been routinely ignored in the past few decades. There is no standing Authorization for Use of Military Force that applies to Iran. If the administration believes direct military action is warranted, it should appear before Congress and make the case to the American people.

Trump, however, is highly unlikely to ask for congressional approval before acting. With a pliant GOP in charge of both houses, he may feel he can ignore Capitol Hill altogether. But Congress could complicate things for Trump, especially if a critical mass of Republican legislators began to oppose U.S. military action. Prominent conservatives are already sowing doubt. “I don’t want us fighting a war. I don’t want another Mideast war,” Senator Josh Hawley, a Republican from Missouri and a fervent supporter of Israel, told a reporter from CNN earlier today. “I’m a little concerned about our sudden military buildup in the region,” he added. American intervention, particularly if U.S. service members are killed, could trigger high-profile congressional hearings and vocal opposition in conservative media outlets. This could amplify public skepticism and further erode support for U.S. participation in the war.

Given these strategic, political, and constitutional considerations, the United States should help Israel finish this war on its own, and on its own terms. But that is all Washington should do. This is Israel’s fight, and Israel’s war to win. There is no reason to make it Washington’s war to lose.