On September 12, Secretary of State Mike Pompeo assured Congress that the coalition was trying to minimize civilian casualties and enable deliveries of humanitarian aid to Yemen. Yet his claim contradicted virtually every other independent assessment of the war, including a recent report by a group of United Nations experts and several Human Rights Watch investigations that alleged the coalition had committed war crimes. Meanwhile, in a memo Pompeo sent to Congress, he noted another reason for continued U.S. support for the coalition: containing Iran and its influence on the Houthis.

Like the Saudis and Emiratis, the Trump administration sees in the Houthis the same sort of threat as other Iranian-backed groups such as Hezbollah, which has sent thousands of fighters to help Bashar al-Assad’s regime in Syria. In late August, the U.S. Mission to the United Nations tweeted a photo that had circulated in the Arab press of a meeting in Beirut between the Hezbollah leader Hassan Nasrallah and Houthi officials. U.S. officials claimed it showed “the nature of the regional terrorist threat,” and added: “Iranian proxies in Lebanon & Yemen pose major dangers to peace & stability in the entire Middle East.” But beyond recent missile attacks on Saudi Arabia—in retaliation for Saudi air strikes—the Houthis have displayed little regional ambition. Ironically, as the war drags on, the Houthis will grow more dependent on support from Iran and its allies.

By accepting the coalition’s cosmetic attempts to minimize civilian casualties, the Trump administration is signaling to Saudi and Emirati leaders its apparent belief that a clear military victory in Yemen remains possible. And as long as the coalition believes it can crush the Houthis, there’s little incentive for it to negotiate. Trump, then, has bought into Saudi Arabia’s zero-sum calculation: that a military win in Yemen for the kingdom and its allies would be a defeat for Iran, while a negotiated settlement with the Houthis would be a victory for Tehran. Blinded by its obsession with Iran, the Trump administration is perpetuating an unwinnable war and undermining the likelihood of a political settlement.

This current phase of the conflict in Yemen began in September 2014, when the Houthis, a group of Shia rebels allied with Yemen’s ousted dictator Ali Abdullah Saleh, forced most of President Abdu Rabbu Mansour Hadi’s government to flee to Saudi Arabia, and threatened to take over much of the country. In 2015, the Saudi-led coalition went to war in Yemen to restore Hadi to power and roll back the Houthis. Since then, despite thousands of air strikes and an air and naval blockade at a cost of some $5 to $6 billion a month for Riyadh, the Saudi-led alliance failed to dislodge the Houthis from the capital, Sanaa.

While the Saudis are quick to blame Iran for the war, several researchers, including Thomas Juneau, a professor at the University of Ottawa and a former analyst at Canada’s Department of National Defense, have shown that the Houthis did not receive significant support from Tehran before the Saudi intervention in 2015. Iran has stepped up military assistance to the Houthis since the war, and Hezbollah has begun sending military advisers to train the Yemeni rebels. But the costs of this assistance fall far short of those incurred by Saudi Arabia and its allies. For Iran, the Yemen conflict is a low-cost way to bleed its regional rival.