While the announcement was unexpected, the president has been telegraphing his unhappiness with Syria policy for some time. Last spring, he said, “I want to get out. I want to bring our troops back home.” The Pentagon won a reprieve of “months, not years,” and evidently those months ran out yesterday.

Read: Trump wanted out of Syria. It’s finally happening.

Perhaps the president felt boxed in by establishment national-security figures early in his presidency, as previous presidents have felt boxed in, and those advisers have either been replaced or fallen from favor. But the lack of a process to evaluate the consequences of the policy change, and sync America’s actions with those of the 78 other countries contributing to the counter-ISIS campaign, will distress those who are risking their forces and security.

Kurdish forces in Syria, Iraq, and Turkey will be immediately and negatively affected by the decision. The contradiction inherent in the previous policy was that the United States armed and relied on Kurdish military forces that the Turkish government considers terrorists. But the U.S. has not been able to find common cause with Turkey in six years. By abandoning the Kurds—who do share American objectives—the U.S. leaves them to the mercies of Turkey even as it leaves Syria to Iran and Russia. Erdogan, Putin, Assad, Khamenei, and Soleimani must be drunk with their good fortune.

This decision will also unsettle every ally that relies on American security guarantees. The governments of Iraq and Afghanistan ought to be very, very worried. For if Syria can be so lightly written off, the fight arbitrarily declared won, what is the argument for continuing to assist Iraq—where ISIS is even more defeated? And if Trump has so little interest in stabilizing security and assisting governance in Syria, how can Afghanistan have confidence that he won’t make the same decision about them, when the fight there is costlier and progress less evident?

Hassan Hassan: ISIS is poised to make a comeback in Syria

White House Press Secretary Sarah Sanders announced, “The United States and our partners remain committed to eliminating the small ISIS presence in Syria that our forces have not already eradicated.” Keeping allies in Syria will be a neat trick, given that the Trump administration had been twisting arms and promising an enduring American commitment. France and Britain are left exposed, as they may not be able to unwind their operations on America’s timeline. And they will fear that jihadist fighters will return to Europe if they are not tied down by operations on Syrian battlefields.

The president’s national-security strategy states, “­The campaigns against ISIS and al-Qa’ida and their affiliates demonstrate that the United States will enable partners and sustain direct action campaigns to destroy terrorists and their sources of support, making it harder for them to plot against us.” President Trump’s decision yesterday proves that irrelevant.