The announcement by US President Donald Trump on December 19 of his intention to rapidly withdraw US forces from eastern Syria led to expectations of a rapid move by Turkish forces into all or part of the area currently controlled by the US-aligned, Kurdish-dominated Syrian Democratic Forces.
The precipitating factor that led to Trump’s announcement, after all, was a phone call between the president and his Turkish counterpart, Recep Tayyip Erdogan. For Turkey, control by what Ankara regards as the Syrian franchise of the PKK of a large swath of the 900-km. Syrian-Turkish border has long been seen as entirely unacceptable.
The Kurdish dominated SDF has capable and proven fighters. But without US help, and facing Turkish air power and artillery, they would be able to resist only for a while. This had already been proven in Turkey’s Operation Olive Branch in January 2018, when Ankara invaded and destroyed the Kurdish canton of Afrin in northwest Syria.