Smoke rises over Kobani, in northern Syria, following fighting between the Islamic State in Iraq and al-Sham and Kurdish armed groups, October 9, 2014. Photograph by Emin Menguarslan / Anadolu Agency / Getty

Disaster is looming in Syria, again. Fighters from the Islamic State in Iraq and al-Sham, the fanatical group that has conquered swaths of the country, are pushing into Kobani, a Syrian town with a mostly Kurdish population that sits near the Turkish border. Thousands of Kurds have fled, but thousands remain. American and Turkish officials have said that Kobani probably can’t be saved.

This is precisely the sort of debacle that President Barack Obama appeared to be aiming to stop when he announced, last month, that the U.S. military would begin carrying out air strikes against ISIS targets in Syria. (It had been bombing ISIS in Iraq since early August.) American jets have begun hitting the group's trucks and compounds in Syria, including targets near Kobani, but these attacks have not stopped the ISIS advance. Why is the situation turning out so badly?

The answers are pretty simple, and they aren’t exactly heartening. The first concerns our main ally in the region, Turkey, a NATO member and a democracy whose President, Recep Tayyip Erdoğan, promised to help the United States in destroying ISIS. The White House would like Turkey, which shares a five-hundred-mile border with Syria, to help rescue the people of Kobani, an effort that could possibly include sending troops or directing military support across the border. At the same time, the Kurds inside Syria simply want the Turkish government to allow reinforcements to pass through Turkey from other parts of Syria on their way to Kobani. So far, Erdoğan has been happy to let the people of Kobani face ISIS alone. Turkish soldiers are watching the encirclement of Kobani from their positions a few hundred yards away.

We shouldn’t be shocked. The truth is that, when it comes to ISIS, Erdoğan has other priorities. Ever since ISIS's emergence in Syria, in late 2012, Erdoğan, an avowed Islamist politician, has maintained a less than hostile relationship with the group. Indeed, since 2011, when the Syrian civil war broke out, Turkish officials have allowed hundreds, if not thousands, of militants to travel through Turkey and cross into Syria to fight the government of Bashar al-Assad. Border agents haven’t exactly quizzed the fighters about which groups they intend to join when they get there. The Turkish government has provided money and support for all manner of Syrian opposition fighters, often so indiscriminately that money has ended up in the hands of groups like ISIS and Jabhat al-Nusra, the local Al Qaeda franchise. When Vice-President Joe Biden publicly complained about this last week, Erdoğan threw one of his typical—and, in this case, utterly disingenuous—temper tantrums, demanding an apology. Biden hadn't misspoken; the problem for Erdoğan was that he had spoken the truth. (It’s a tendency that, as Evan Osnos has written, has gotten Biden in trouble before.) Biden should have stuck to his guns; unfortunately, he apologized. There have been persistent reports of wounded ISIS fighters receiving treatment in Turkish hospitals close to the border with Syria. What it comes down to is that ISIS has been pursuing a policy that Turkey strongly favors—the overthrow of Assad—and Turkey, for that reason, has been reluctant to join in the fight against the extremist group.

The second reason that the Turks are reluctant to save the Kurds in Syria is because they are Kurds. The far northeastern corner of Syria is mostly Kurdish, as is the area across the border in Turkey. (As is northern Iraq; I wrote last month about the Iraqi Kurds and their quest for independence.) For years, the Kurds in Turkey have been battling the central government for more rights; the Turkish government has often responded brutally, arbitrarily, and disproportionately. In Turkey, the Kurdish revolt has been led by the Kurdish Workers Party, or P.K.K., which has its own ruthless reputation. Its Syrian affiliate, the Democratic Union Party, is one of the dominant parties in northeastern Syria. To put it mildly, Turkish governments are not in the habit of helping Kurds, and certainly not the P.K.K.

Indeed, some Turks are so hostile to the Kurds that they have thrown their sympathies in this battle behind ISIS: during a recent gathering of Kurdish protesters in Ankara, the Turkish capital, Turkish police moved in holding their index fingers in the air—the same symbol that ISIS militants use when beheading prisoners. It is really not so surprising that Erdoğan would be reluctant to send his troops into Syria to save a group of embattled Kurds.

But the real problem for Kobani is American policy. In August, when President Obama announced that he would launch air strikes to “degrade and destroy” ISIS, he emphasized that he had no intention of sending American combat troops into Syria. What is happening now is a classic problem of diplomacy: a mismatch between means and ends. President Obama wants to destroy ISIS and save the Kurds (and the Yazidi religious minority, and the Iraqi government in Baghdad), but he is willing to do no more than drop bombs. What happens when dropping bombs isn’t enough?

In Kobani, it seems, we are about to find out.