This first became widely known when the U.S. decided to remove our troops from the war in Vietnam, Laos, and Cambodia in the 1970s. Many of our allies in those nations were left high and dry , to be persecuted or slaughtered by the communists. In Cambodia, after the U.S. left, the genocidal forces of Pol Pot killed up to two million people .

More recently, in 2011, U.S. troops were prematurely recalled from Iraq, abandoning the persecuted minorities there. This allowed ISIS to establish the caliphate and slaughter and terrorize the population, especially Shia Muslims, Yazidis, and Christians. Because ISIS was an avowed enemy of the U.S., beheaded several of our citizens, and conducted terror attacks against us, the U.S. eventually had to return to stop it.

Ironically, America becomes an undependable ally often because the American people have moral values and do not want to fight or police other nations. Also, as a democracy, the U.S. public is sensitive to American casualties. So when a war goes on too long, with many casualties, we often turn against the war, regardless of its importance or which side is winning.

This need not be what happens, in Syria, today.

The U.S. has about 1,000 American troops in Syria. American troops were first introduced in 2014 to provide supplies, training, and air support to the Kurdish fighters in Syria and, later, the Syrian Democratic Forces (SDF), which included the Kurds, Syrian Sunni Arabs, Christians, and Yazidis as well.

These U.S. troops have done a fantastic job, in tandem with the SDF. In 2017, at the behest of the U.S., U.S. forces and the SDF conquered Raqqa, the capital of the ISIS caliphate. In 2019, they seized the last land area in Syria controlled by ISIS.

It is important to realize that the SDF had no reason on its own to conquer these areas, which are heavily Sunni Arab. They did this at the behest of the U.S.

Another important point is that from 2014 through today, only eight U.S. citizens have been killed in Syria. This is because only very rarely were the U.S. forces anywhere near the front lines.

The SDF, through its civilian political party, the Syrian Democratic Council, has set up a self-governing area in Syria, constituting about a third of Syria. Although the SDC rule of this area has not been perfect, it has been much more secular, democratic, and pro–human rights than any other group in Syria or Iraq. What is especially notable in this area is that women, who, outside Israel, are largely discriminated against throughout the Middle East, are given real power in the SDC government.

This SDF-controlled area notably includes 80% of the oil supplies in Syria.

But now, the Turks, led by their Islamist dictator Recep Tayyip Erdoğan, are pressuring the U.S. to abandon the SDF. President Erdoğan wants to create a "safe zone" that would extend 20 miles south from the Turkish border. And he wants this area to be free of SDF forces. The problem with this is that the "safe zone" that Erdoğan wants to create would incorporate a huge majority of the Kurdish population. As we have seen from Afrin, if the Turks are successful in creating this zone, they will ethnically cleanse the native Kurdish population, which Erdoğan has long hated and feared, and replace them with the 3.5 million Sunni Muslim Arabs who are refugees in Turkey. Also, as we have seen in Afrin, the Turks will replace the budding Syrian democracy with Turkish rule that is Islamist, is largely undemocratic, and does not respect human rights.

This is the same Turkish regime that has increasingly become a fierce U.S. opponent, assisting both ISIS and Iran; buying the S-400 missile system from the Russians; threatening its neighbors, including Greece, Cyprus, Israel, and the various Kurdish entities (all of which are pro-American); and backing the terrorist Muslim Brotherhood throughout the Middle East.

The Turks are not the only ones who want the U.S. troops out of Syria. The Russians, the Iranians, and the Assad regime also want them gone. These dangerous actors hope to eventually reconquer most of this area for Assad.

The U.S. has agreed to a Turkish "safe zone" but has been ambiguous about the specifics. When it comes to the latter, the U.S. needs to keep true to its ally, the SDF. Otherwise, this would endanger U.S. forces — what nation would want to ally itself with us during future conflicts? If the U.S. abandons the SDF, it will allow Turkey to wipe out the SDF; ISIS to rebound in the south of the SDF controlled area; or the Russians, the Iranians, and Assad to gain control of this area.

It would also allow our enemies to gain control of the oil fields. I suspect that President Trump would rightly be concerned about this.

The U.S. should limit the safe zone in Syria to the smallest area possible and tell Turkey to stay out of any other SDF-controlled lands in Syria. If Turkey refuses to listen, sanctions can be imposed. And the U.S. troops in the area should stay put. Otherwise, once again, the U.S. will become an undependable ally.

Adam Turner is the general counsel and legislative affairs director for the Endowment for Middle East Truth (EMET).