President Trump dropped a stunner during his rambling press conference, on Sunday, after announcing the death of Abu Bakr al-Baghdadi, the Islamic State leader, in a U.S. raid. In a major policy flip-flop, the President said that he is not only keeping American forces in Syria to “secure” its oil fields, he is willing to go to war over them. “We may have to fight for the oil. It’s O.K.,” he said. “Maybe somebody else wants the oil, in which case they have a hell of a fight. But there’s massive amounts of oil.” The United States, he added, should be able to take some of Syria’s oil. “What I intend to do, perhaps, is make a deal with an ExxonMobil or one of our great companies to go in there and do it properly,” he said. The goal would be to “spread out the wealth.”

The President was wrong on so many counts. Seizing the oil, after twice ordering all U.S. troops out of Syria, violates a basic international treaty on war. It may amount to pillaging—even piracy, according to legal experts and former senior military commanders. “Bring in US oil companies to modernize the field. WHAT ARE WE BECOMING.... PIRATES?” General Barry McCaffrey (Ret.), who commanded a mechanized Army division in Iraq during the Gulf War, tweeted.

Trump’s new policy may also violate the military authorization from Congress which allowed the United States to enter Syria. It certainly violates Syrian sovereignty. “If ISIS is defeated we lack Congressional authority to stay,” McCaffrey tweeted. “The oil belongs to Syria.”

Trump’s suggestion that the U.S. could expropriate a portion of Syria’s oil “sounds like the international crime of pillage,” Ryan Goodman, a former special legal counsel at the Department of Defense who is now at the New York University School of Law, said. Any such move is prohibited by the Geneva Conventions and by the precedents set by the United Nations war-crimes tribunals that the U.S. helped establish in Yugoslavia, Rwanda, and Sierra Leone. “U.S. military commanders who engaged in pillaging Syria’s oil would risk criminal liability under the U.S. War Crimes Act,” Goodman said. The international rules of war, he added, were designed “to deter nations from engaging in predatory wars to seize other countries’ natural resources.”

Most of all, the new policy—which may keep some five hundred American troops in Syria—wasn’t well thought out, U.S. officials and Middle East experts told me. “It was seat-of-the-pants type shit,” a U.S. official said. Another told me, “To say the oil stuff isn’t thought through is an understatement. The N.S.C. is scrambling to build policy around the President’s tweets.” Joshua Landis, a Syria expert at the University of Oklahoma, described it as “cockamamie.”

What’s particularly baffling is that Syria now produces a piddling amount of oil—about as much as Utah. “Syrian oil was not significant at all to the world market. It was very small,” Daniel Yergin, an energy expert and vice-chairman of IHS Markit, told me. At its peak, Syria produced less than four hundred thousand barrels a day, which generated about a quarter of government revenues. But, as a result of the eight-year civil war and U.S. air strikes on oil installations seized by ISIS, production is down ninety per cent, to only about forty-thousand barrels per day, Yergin said. That’s a negligible amount on global markets—inadequate even for Syria’s domestic needs.

After ISIS seized a third of Syrian territory, in 2014, oil became the financial lifeblood for the ISIS caliphate. “Syrian oil took on global interest when it became a machine for generating revenue for ISIS,” Yergin said. As the caliphate collapsed, the Kurdish-led Syrian Democratic Forces took over running the fields. Oil revenues supported its military and civilian programs.

As justification for redeploying U.S. forces, Trump cited the need to prevent ISIS from returning to the resource-rich area. “We’re securing it for a couple of reasons,” he said. “No. 1, it stops ISIS, because ISIS got tremendous wealth from that oil. We have taken it. It’s secured.” The other reason is that it helps America’s Kurdish allies. “They were able to live with that oil,” he added.

In March, I travelled throughout the northeastern third of Syria, where the bulk of Syria’s oil fields are located. The al-Omar oil field, in the province of Deir Ezzor, near the border with Iraq, had been destroyed by U.S. air strikes. It was the largest oil field seized by ISIS; its rigs and storage facilities were rusted, burned-out ruins. U.S. Special Forces and the S.D.F. used the housing compound next to the fields as a forward operating base. I stayed there during the final offensive against ISIS at Baghouz. Rigs in smaller oil fields farther north were still pumping. The S.D.F. had converted an abandoned compound for an oil field in Dashisha into a makeshift prison for captured ISIS fighters. From the rooftop of the prison, I could see vintage pumps pulling up oil. On a highway near Al Hasakah, near the Rumeilan fields, I counted forty-four oil tankers in a single convoy—for security—going in one direction, and thirty-seven tankers going the other way. Through intermediaries, both ISIS and the S.D.F. sold oil to Damascus, U.S. officials told me.

Senator Lindsey Graham, the South Carolina Republican and staunch Trump supporter, was the chief advocate for the President’s proposal to secure and control Syria’s oil. As with many other Republicans on the Hill, Graham condemned Trump’s abrupt announcement, on October 13th, of the plan to withdraw a thousand U.S. Special Forces soldiers from Syria, on the grounds that the U.S. would be abandoning its S.D.F. partners who had defeated ISIS. He has lobbied hard for the White House to rethink its position, and touted access to Syrian oil as an incentive. “By continuing to maintain control of the oil fields in Syria, we will deny Assad and Iran a monetary windfall,” Graham said last week. “We can also use some of the revenues from future oil sales to pay for our military commitment in Syria.”

It fit with Trump’s longstanding position that the United States should seize the oil of other countries to pay for its military campaigns. “In the old days, you when you had a war, to the victors belong the spoils. You go in. You win the war and you take it,” Trump said, in 2011. “You’re not stealing anything. You’re taking—we’re reimbursing ourselves—at least, at a minimum.”

The United States, however, cannot legally seize Syria’s oil or benefit from it, a State Department official told me. Any military action to protect the oil fields of another country—without its consent—is dubious. “The United States is on even weaker legal ground since President Trump has said that there is no reason for the U.S. to be fighting ISIS to protect the U.S. homeland,” Goodman told me. “So the basis for a claim that this military operation is in self-defense against a terrorist group posing a threat to the United States has gotten a whole lot weaker.”