The Middle East has once again been plunged into strife and uncertainty—and the primary culprit is the American president who promised to end the U.S. habit of engaging in “forever wars”: Donald J. Trump. By joining with Israel to carry out the targeted killing of Iran’s supreme leader, Ali Khamenei, Mr. Trump has ignored U.S. law to involve the country in a war solely on his own authority. He also continues to ignore the costs and risks of destabilizing the already fragile international order. As the editors said about his adventurism in Venezuela only two months ago, “Unprincipled and unpredictable military intervention will make regional conflicts more enduring and destructive.”

It should go without saying that opposition to the joint U.S.-Israeli attack on Iran is by no means an endorsement of the existing Iranian regime, as if two bad options were the only possibility: Violently destroy the regime or support the regime. Decades of totalitarian rule and the violent suppression of civilian protest, combined with support for proxy wars aimed at undermining the stability of the region and defiance of U.N. resolutions regarding nuclear weapons development—along with regular calls for the literal destruction of the United States and Israel—have rightfully made the Iranian regime a pariah. But acknowledging that reality does not justify regime change by force nor does it render that outcome practically achievable.

The political calculus of the Trump administration thus far suggests a willingness to let the end justify the means: Once the opportunity to eliminate Iranian leadership through decapitation strikes presented itself, it was too good an opportunity to pass up, regardless of what was happening at the negotiating table. However, that reasoning not only fails to meet the criteria for military action in any formulation of just war theory or international law, it also fails the test of common sense. What is the end that is supposed to justify these dangerous and unpredictable means? 

Is it regime change, as Mr. Trump said in two video messages over the weekend after airstrikes had begun? Is it a further attempt to destroy Iran’s nuclear program, after this summer’s strikes? The elimination of any missile threat to the United States and Israel? Or, as Secretary of Defense Pete Hegseth said in a press conference this morning, is the goal simply to deliver the message, “If you kill Americans, if you threaten Americans anywhere on Earth, we will hunt you down without apology and without hesitation and we will kill you”? It is not clear that anyone in the U.S. government—and certainly not in the international community—knows what the desired end is at all.

Anyone with a memory of 2003 and the lead-up to the second Gulf War against Iraq will also recall another lesson the United States learned the hard way: U.S. military adventures in the Middle East tend to end very, very badly. That second war resulted in massive civilian and military casualties and caused the Iraqi state to all but cease functioning. Even today, a quarter of a century later, Iraq remains a fractured and violent shell of a nation. In the meantime, U.S. forces remained on the ground in Iraq for decades after President George W. Bush declared “Mission Accomplished.” American action against Iraq in 2003 also contributed to the rise of ISIS and the ensuing Syrian Civil War, leaving that country destitute as well. 

In 2003 (and in 1991), the U.S. government sought to convince its own citizenry and the international community, including the Vatican, of the need for military intervention in Iraq before it undertook the actual invasion. Even in 2003, when the United States acted with a far smaller coalition of nations than in 1991 and on what was later revealed to be puffed-up evidence of an Iraqi nuclear weapons program, George W. Bush’s administration at least went through the forms of seeking some Congressional authorization and international consensus before military intervention. This time around, Mr. Trump made no such attempt. 

Perhaps recognizing he would not receive the support of Congress, particularly in light of the public defections by Rand Paul and other prominent Republicans, Mr. Trump chose instead not to bother. Neither did he attempt to make a public case to the American people, only one in four of whom support the strikes on Iran, or to the international community.

Is there a way out of this moral and legal morass? Given that Mr. Trump’s capacity to start a war far exceeds his ability to end one, what should the United States do in Iran going forward, now that it has killed much of its senior leadership but has no credible way to empower any alternative to the current regime? 

The first step is for Mr. Trump to stop—or for Congress to stop him—from directing this war haphazardly with unclear and unrealistic goals. Robust bipartisan cooperation in response to the president’s actions is needed: An open and unfettered debate in Congress that includes the forthright voices of Republican legislators speaking out against the war might convince Mr. Trump to return to the negotiating table and to formulate a plan that he could defend to allies at home and abroad. Sadly, the United States will probably need to plan for an end to this conflict without relying on Western allies. We cannot count on the international community, in large part because in the past 15 months, most of the international community has learned to stop counting on us. 

There is no question that we are facing a domestic and international emergency as the bombs continue to fall. While we still hold out hope for a return to diplomacy and respect for the rule of law, we also face a worst-case scenario, one named aptly by Pope Leo XIV soon after the attacks began: that we will not be able to “assume the moral responsibility of halting the spiral of violence before it becomes an irreparable abyss.”