This week, it was announced that our 2,000 or so troops would be pulled out. Job done, go home, right?

In the midst of the Vietnam War, Sen. George Aiken is reported to have said, "Let's just declare victory and get out." In October, President Donald Trump did " declare victory " over ISIS. "I want to get out," the president said. "I want to bring our troops back home. I want to start rebuilding our nation."

There was a bit of a hedge by the Pentagon. Chief spokesperson Dana White said the campaign against ISIS is "not over," but "we have started the process of returning U.S. troops home from Syria as we transition to the next phase of the campaign. We will continue working with our partners and allies to defeat ISIS wherever it operates."

OK, still, we're pretty much done, right? In the narrowest sense, perhaps, although ISIS remains a regional scourge. But it raises the question of what to do when your war aims change in the middle of the war. The defeat of ISIS was, clearly, the first American goal. We were not involved in the Syrian civil war and not planning to be. So American forces took on what appeared to be a limited job. But nothing is limited in the Middle East.

By design or default, United States forces were serving two other functions. In September, secretary of state Mike Pompeo and national security adviser John Bolton made the case for Iran's continued presence in Syria creating instability that presented a strategic threat to American interests in the region – and would allow Iran to control the "Shiite Crescent" from Iran through Iraq, Syria, and Lebanon to the Mediterranean Sea.

The U.S. had hoped Russia would help disengage Iran. Russia declined, leaving Washington to figure out how to block the Iranians on their march. One way was to support Kurdish forces that presently hold ground amounting to about 30 percent of Syrian territory. They stretch along the Turkish border in the north, to and along the Iraqi border in the east. Syrian Sunni rebels – including jihadists as well as secular Sunnis and allies of Turkey – hold territory in the north, but farther to the west.

Kurdish groups in Iraq and in Syria have been America's most reliable ally. Fighting Saddam, fighting ISIS, rescuing Yazidis in Sinjar, avoiding radicalization, and having relations with Israel, Kurds are, perhaps, the most forward-thinking group in the region. Our support is physical; financial; and, perhaps most important, a warning to others that the Kurds have powerful friends.

America's support for the Kurds – America's other function in Syria – is what presents the problem.

Turkey considers all Kurds terrorists and has instigated battles against their Syrian territory from inside Turkey as well as from inside Syria. Turkish forces have been careful not to involve American troops. Mostly. But according to the Army Times, Turkey has been increasingly belligerent, raising the odds of a U.S.-Turkey clash. That would be a military engagement between two members of NATO – an engagement that could have ramifications well beyond the immediate region.

America's relations with Turkey have been contentious at best, and not only over the Kurds. Turkey's growing closeness with Russia and Iran (its two historic enemies), its increasingly heavy-handed tactics at home against journalists and regime opponents – including kidnapping some from Europe, its support for Hamas, and rhetoric against Israel – have made it a difficult member of NATO, to say the least.

The contents of President Trump's phone call with Turkish president Erdoğan on Wednesday are not public, but it was at the end of that call that the president made a point of the troop withdrawal. It is hard to avoid the uncomfortable – no, the downright nauseating – thought that the United States agreed to open the way for Iran to reach the Mediterranean Sea by abandoning our Kurdish allies for a somewhat less truculent Turkey.

But isn't it right for President Trump to do what he said he would do?

OK. So bring the troops home from Afghanistan, where American soldiers have been for 17 years, incurring nearly 2,500 American and more than 360,000 Afghan deaths (not to mention thousands of long-term injuries) and spending nearly $1 trillion in U.S. funds in the vain hope that a corrupt, secular-ish government in Kabul could make "peace" with its cousin, the jihadist Taliban revolutionary army harbored in Pakistan and funded by Iran. Coming home from there would make sense. The Afghan civil war is not our war, nor is there a broader strategic interest there. Yes, it may again become a haven for people who want to kill us. But so could any country in the region, most of the Middle East, and much of Africa. Whether they do or they don't is more a matter of Iranian involvement than anything else.

This brings us back to Iran.

It is not our job to occupy all the countries that may harbor those who seek to do us ill. But to offer Russia, Iran, and Turkey – not to mention Syria's war criminal president, Bashar Assad – a victory at the expense of Sunni Syrians and our Kurdish allies is, not in Aiken's words, "a victory," but is what in Yiddish is called a "Shonda."