The first thing that will happen is that YPG forces south of the invasion line will abandon their posts to join their comrades up north, unspooling some of the much-needed security blanket which has enveloped Raqqa and Deir Ezzor to forestall the return of ISIS.
The second thing that will happen is the Kurds, absent air support, will be beaten and Turkey will ethnically cleanse the territories it takes from the YPG.
And that brings me to the third thing that will happen, which, even if you can’t tell a hawk from a handsaw in this forbidding war zone, should have you worried.
For years, ISIS has watched as America’s reliance on the YPG/PKK has enervated the second-largest army in NATO. It has cleverly preyed upon this tension by waging terror attacks in Turkey it declined to claim credit for, knowing full well that Erdogan and his government might blame them on the PKK, which it did on more than one occasion.
Turkey, meanwhile, had maintained a see-no-evil policy (or worse) with respect to ISIS as its sovereign territory became a staging ground for exported jihad, not to mention a fallback base of operations for the many agents of ISIS’s Amniyat, or intelligence service, who were dispatched out of Syria and into Western Europe.