Baderkhan Ahmad / AP

Here are the terms of the deal: Turkey takes responsibility for the 11,000 imprisoned ISIS fighters, and 70,000 collaborators now held in the al Hawl and Ain Issa detention camps by Syrian Democratic Forces; and the U.S. withdraws its forces from northern Syria so Turkey can invade. Turkey will establish a 30-kilometer zone into which it will forcibly repatriate 1 million Syrian refugees on Turkish land. It will combat both the Kurdish forces that have been fighting ISIS and the Syrian Democratic Forces that are the last obstacle to Bashar al-Assad fully controlling Syrian territory. Because the U.S. persuaded the Syrian Democratic Forces to dismantle their defenses as a confidence-building measure between the SDF and Turkey, they are defenseless against the Turkish onslaught.

The deal achieves President Donald Trump’s objective of withdrawing U.S. military forces from Syria, something he has been agitating to do since December of 2018—when his announcement to that effect precipitated the resignation of Secretary of Defense James Mattis. Sunday night’s abrupt policy shift, delivered after a call with Turkish President Erdoğan, appears to have caught his current secretary of defense equally off guard; Mark Esper tweeted on Monday that “the Department of Defense made clear to Turkey—as did the President—that we do not endorse a Turkish operation in Northern Syria … We will work with our other NATO allies and Coalition partners to reiterate to Turkey the possible destabilizing consequences of potential actions to Turkey, the region, and beyond.” (He has since deleted the tweet, but not retracted the statement.) And just a few days ago, the U.S. European Command was extolling Turkish-SDF cooperation, suggesting that the president’s agreement with Erdoğan was truly unexpected.

But the internal U.S. process isn’t the point: The president can make foreign-policy decisions any way he wants to. He’s the one who got elected. It may be unwise not to seek the counsel of the experienced national-security hands who’ll carry out his policy. As commander in chief, however, he can skip over an interagency process that vets decisions and keeps everyone informed. Nor does it matter that the president disdains military advice. That, again, is the prerogative of our elected chief executive.

The problem is not the process, it’s the policy. As former U.S. Envoy Brett McGurk explained the last time the president wrote off Syria, the most important consequence of this decision is the effect it will have on U.S. allies. The U.S. has achieved the territorial defeat of ISIS with only five U.S. combat deaths, while more the 10,000 members of the SDF forces were killed. We are, then, abandoning partners, Kurds and the SDF, that fought alongside us because we have similar interests—in order to placate the concerns of a partner, Turkey, that does not share our interests.  

The sound of U.S. abandonment will be heard beyond the Middle East. The 81 countries participating in the anti-ISIS coalition who have not been given notice of the Trump administration’s decision will all be scrambling to get out of Syria and Iraq before U.S. assistance evaporates. It will be much harder to persuade those countries in the future to contribute to problems the U.S. wants solved, because we have disrespected their contributions and disregarded the political problems that explaining our actions to their citizens will create for them. We should also expect countries that are most reliant on U.S. security guarantees to search for alternatives—to the detriment of our interests on the Korean Peninsula, in Europe, and in Afghanistan.  

The White House emphasized that the ISIS caliphate has been defeated. And it is true that ISIS holds no more territory in Syria or Iraq. But ISIS was enabled by political and security crises in Syria and Iraq—and Syria and Iraq remain in crisis. Assad continues his brutal subjugation of the last areas not yet under regime control, and there’s little prospect that he will provide for the reconstruction of what he, the Russians, and Iranians have destroyed. Riots erupted in Iraq five days ago over exasperation with the corruption, mendacity, and Iranian tilt of the political elite; more than a hundred people have been killed and thousands wounded, including from government forces firing on crowds.

Does the U.S. truly intend to ignore these wildfires in Syria and Iraq? They create opportunities for the resurgence of violent jihadism, may spur violence beyond the Middle East into our own society, exacerbate the terrible human suffering of Syrians and Iraqis, and increase the likelihood of another refugee outpouring. This is a time for more U.S. diplomatic and military involvement, not less.

Even if the Trump administration doesn’t care about the welfare of either Iraqis or Syrians, and even if Trump doesn’t think we’ll ever want allies to share our burdens, his agreement with Turkey cedes the field of influence to Iran. And wasn’t the prevention of that outcome supposed to be the administration’s central objective in the Middle East?  

The secretary of defense and chairman of the Joint Chiefs of Staff have both emphasized that the U.S. will not assist the Turkish invasion. But we already have, by standing aside while Turkey demonstrates to those who would ally with the United States for common purpose, that neither allies nor common purpose matters much to the Trump administration.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.