Turkey has been fighting several terrorist groups on different fronts in Syria and Iraq, such as the PKK, the PKK’s Syrian offshoot the Peoples’ Protection Units (YPG) and Daesh. Even though Ankara remains an important NATO ally for Washington, its national security is threatened by the activities of these groups while the US looks on.

It is no secret that the US arms and trains YPG militants who supposedly fight Daesh in Syria. In spite of Ankara’s repeated calls on Washington to stop collaborating with the YPG – which it considers to be a terrorist group – the US calls the YPG its “strong partner”.

Recently, the US-backed Syrian Democratic Forces (SDF), mostly consisting of YPG militants, launched an operation to retake Daesh’s “capital”, Raqqa. The move was seen by Ankara as a stab in the back from a NATO ally.

The Turkish public fails to understand why the US chooses to cooperate with a terrorist group on the ground rather than its ally Turkey. President Recep Tayyip Erdogan sent a message to the US, saying that the Turkish military is ready to join forces to retake Raqqa from Daesh. Washington, though, remained apathetic and sided with the YPG-dominated SDF in the Raqqa operation. It was the latest disappointment in an already strained Turkish-US relationship.

Ankara and Washington cannot find common ground on Manbij either. The River Euphrates has been a red line in Ankara for quite a while; the Turkish authorities have asserted repeatedly that the PKK-affiliated YPG cannot stay west of the Euphrates and have called on the US to force the YPG out of the area.

The YPG militants have recently announced that they were leaving Manbij and retreating east of the Euphrates. However, the truth rose to the surface very quickly. Yes, the YPG militants moved away from Manbij, but towards the west. The YPG-dominated SDF has been marching towards the significant northern Aleppo town of Al-Bab.

The YPG, armed by the US, has been attacking Turkey around Al-Bab. The Turkish military-backed Free Syrian Army (FSA) has been engaging in clashes with the YPG. The race for Al-Bab tightens as the FSA and the YPG are trying to seize the town from Daesh.

Even though the US-led coalition should be backing the FSA with air strikes, coalition spokesman John Dorrian said last week that its fighter jets do not carry out air strikes to support the FSA on the ground.

The current situation around Al-Bab shows clearly that America’s policy in Syria has failed miserably. The US looks on as a NATO ally is being attacked by a terrorist group using US-supplied weapons and equipment.

However, Ankara is hopeful that US President-elect Donald Trump could change the status of Turkish-US relations. The Obama administration has not abstained from supporting and arming the YPG in the face of Turkish concerns. Ankara wants to welcome the Trump administration with a different perspective.

President Erdogan stressed recently that before the election Trump and his closest advisors voiced policies close to that of Ankara on Syria and Iraq. Turkey has a plan in Syria; Erdogan has already mentioned a 5,000 square kilometre safe zone. To accomplish that, the Turkish military is expected to back the FSA until YPG-held Manbij and Afrin are taken after Al-Bab.

“Declaring a no-fly zone is very important, which the Trump campaign supported,” explained Erdogan. “A no-fly zone would be the first step towards a safe zone.” He has been speaking quite optimistically about the Trump administration after the disastrous Obama era. Even if Trump’s Washington follows a similar policy in Syria to that of Obama’s, Turkey will insist on its ambitions to push Daesh further northwards and drive the YPG out of Manbij and Afrin.

Furthermore, the YPG poses a national security threat to Turkey not only in Syria but also at home. Recently, an arrest warrant has been issued for Democratic Union Party (PYD) leader Saleh Moslem. He is accused of orchestrating a terrorist attack that took place in February in the Turkish capital Ankara. The bombing killed 29 people and wounded more than 60.

Ankara also asserts that there is no difference between militants of the PKK and the YPG. As the Turkish military conducts counterterrorism operation in the country’s south-east, Ankara has another red line when it comes to tolerance of the YPG.

In conclusion, Washington will have to find a way to sort out its problems with Ankara to prevent its NATO ally from being attacked by hostile groups in Syria and Iraq. Turkey offers the US broad and open cooperation on the ground if the latter stops collaborating with groups that the former considers to be terrorists.

The views expressed in this article belong to the author and do not necessarily reflect the editorial policy of Middle East Monitor.