The Syrian Democratic Forces were the only local army capable of beating the Islamic State, and in pushing ISIS out of its strongholds—including the caliphate’s capital, Raqqa—the Syrian Kurds paid a heavy price. America will now leave them to their fate. Turkey considers the People’s Protection Force, or YPG, to be terrorists indistinguishable from the Kurdish Workers’ Party in Turkey, and nothing now prevents the Turkish army from a murderous attack on the Syrian Kurds. In a phone call four days before Trump’s decision, Recep Tayyip Erdogan, Turkey’s autocratic president, played him perfectly, flattering Trump by telling him that, with ISIS defeated, Turkey could take it from here—so why would America stick around for the Kurds? “You know what?” Trump reportedly said. “It’s yours. I’m leaving.” It’s yours—do what you want with it. Now that he’s rid himself of every U.S. official willing to tell him what he doesn’t want to hear, Trump can turn for policy advice to foreign dictators.

Read: The Kurds are betrayed again by Washington

The American troops in Syria were never easy to explain. Since a final victory over the Islamic State isn’t possible, what was our goal? Not to end the Syrian civil war—that has never been a serious American aim, since it would require a military and diplomatic commitment that American voters and their elected leaders have no interest in making. The most that Americans have tried to achieve in Syria is to mitigate the worst—to deter Bashar al-Assad from gassing his own people, to stabilize areas occupied by the Syrian Democratic Forces, to counteract Russian and Iranian influence, to keep the Islamic State on the run, to prevent Turkey from slaughtering the Kurds. Those goals suggested an American presence, however small, without end.

Trump looked out across this unsatisfying landscape and saw another way, one more in tune with his own psychic needs, and perhaps with the real desires of most Americans: Declare victory and get out. Claim credit for both the win and the withdrawal. When our enemies return and our friends are wiped out—for not even Trump can believe that this is unlikely—find someone else to blame.

There’s a history behind Trump’s sudden decision. In the face of a war that offers no prospect of complete victory, or any victory, the temptation to betray an ally and call it success has seduced far more serious presidents than Trump. The historical pattern is instructive, and so is the fact that, this time, there’s a difference.

By 1969, the Vietnam War was lost. Instead of telling the American people this hard truth, the new president, Richard Nixon, and his national-security adviser, Henry Kissinger, spent four more years in pursuit of what Nixon called “peace with honor.” He wanted to find a way out of Vietnam that wouldn’t hurt his reelection chances or his broader foreign policy. He wanted to be able to say that 58,000 Americans did not die in vain.