Trump’s shocking Syria decision and confusing aftermath, explained

The White House announced that US troops were leaving part of northern Syria, allowing Turkey to invade and directly threatening the US’s biggest partner in the fight against ISIS.

The war in Syria is about to enter an uncertain phase after the White House announced late Sunday that it was withdrawing from northeastern Syria in advance of Turkey’s military operations across the border.

This directive — which apparently blindsided allies and lawmakers and national security officials alike — leaves the American-backed Syrian Democratic Forces (SDF), largely made up of Kurdish...