Kurds drive a wedge between US and Turkey

Turkish-American relations went through a honeymoon period at the beginning of Obama administration. The Arab Spring added a new context to them. Cooperation continued at the early stages of the Syrian crisis until their policies parted after the chemical attack in Ghouta in 2013. 
The next milestone is the beginning of the Trump administration. Turkey hoped that relations could be brought back to the good old days, but this did not materialize. 
Now they are being put to a more challenging test because of Washington’s pro-Kurdish policy. The Syrian crisis opened up new avenues to carry forward the traditional American support for this cause. Washington believes that the Kurdish fighters of the People’s Protection Units (YPG) are the most reliable US allies in the fight against Daesh. Using this cooperation as a pretext, Washington provides the Kurds with a massive supply of arms and ammunition, including AT-4 anti-tank guided missiles, and tells Turkey that it will continue to do so until Daesh is defeated in Raqqa. It promised Ankara that these weapons would be taken back after the Raqqa operation, but few in Turkey believe that this is feasible. 
Ankara’s efforts to persuade Washington to carry out the Raqqa operation against Daesh in cooperation with the Turkish army did not yield any concrete result.
Now there are two more concrete issues: Afrin and Idlib. The YPG and its political branch, the Democratic Union Party (PYD), proclaimed autonomy in Afrin in January 2014. For understandable reasons, Turkey regards this as an attempt to enclose it in the south and cut it off from the Arab world. President Erdogan is determined to undo this initiative, whatever it takes. He even threatened to carry out a military operation in Afrin if it becomes necessary. If this happens, Washington fears that the Raqqa operation will be negatively affected, because the YPG will give priority to holding Afrin rather than fighting to seize Raqqa and hand it over to Arabs eventually. 
Despite Turkey’s legitimate worries about the Kurdish intentions, persuasion may still be a more effective policy than outright military action. Turkey should be able to explain to the international community, beginning with the US, that apart from the Kurds, Afrin is also inhabited by Arabs, Turkmens, Armenians, Assyrians and Circassians. Any attempt to alter this ethnic composition would be a violation of international law.
The situation is complex in Idlib as well. Fighting continues among various groups, even after the terror organization Hayat Tahrir Al-Sham (HTS), the former Jabhat Al-Nusra, gained control of the city. More remnants of Jabhat Al-Nusra still resisting in Eastern Ghouta and other scattered places will probably be forced ultimately to move to Idlib. Once they are there, it is not clear whether major actors in Syria will try to defeat them right away or wait until next year for them to rot.
Each major actor has its own agenda for what should be done after the defeat. Turkey prefers to oust HTS by promoting Ahrar Al-Sham, the Salafist organization that it supports, and put the city under the control of the latter. Kurds will be very much eager to extend the Kurdish controlled corridor to Idlib and come one step closer to the Mediterranean. But the Kurdish dream could be achieved only by uprooting and expelling the indigenous population of the region and replacing them by Kurds or YPG sympathizers brought from other areas, as it did in Kobani in 2015. Turkey fears that the US may support Kurds in many fields, including in capturing and governing Idlib. 
These issues were discussed at length between US defense secretary James Mattis and the Turkish authorities when he visited Ankara last week. All details of the talks have not been disclosed, but the visit to his Turkish counterpart took longer than initially scheduled and, because of this, his appointment with President Erdogan was slightly delayed. This could happen only when a major difficulty arises during the talks. 
The special American envoy for Daesh, Brett McGurk did not accompany Mattis in Turkey although, the day before, he participated in the defense secretary’s talks in Jordan. McGurk was harshly criticized by the Turkish authorities when he intimated that Turkey was tolerating the movement of Al-Qaeda fighters at the Turkish-Syrian border. 
There is no light at the end of the tunnel for the moment in Turkish-American divergence on the Kurdish policy. If Turkey could come up with an exit strategy in its Syrian policy and focus on the weak points of the YPG approach, it may have a better chance to be understood by the international community. This would also contribute to the revival of mutual trust between Ankara and Washington.