Admittedly, Trump the "dealmaker" ought to have brokered something similar before pulling out and before the Turkish Army—and its Sunni Arab Islamist proxies—invaded the region and inflicted significant civilian casualties.
One must admit that a single phone call between Trump and President Erdogan of Turkey has turned the situation in Syria upside down in just over a week. The Kurds have requested protection from Assad's army, Russian troops are now patrolling between the Kurds and invading Turks, and the U.S. is (for once) watching from the sidelines.
The execution has been sloppy, of course—a Trumpian trademark—and the human cost potentially heavy. Nonetheless, the U.S. withdrawal represents a significant instance of the president actually following through on campaign promises to end an endless American war in the Mideast.