President Trump deserves immense credit for reassessing the evidence and retaining 400 U.S. troops in Syria. Russia, Iran, and Syrian dictator Bashar Assad, however, will react furiously to his decision.

Still, the first point to make here is that Trump’s decision is absolutely the right one. Split between the garrison at At Tanf, close to the Jordanian-Iraqi border, and a garrison in Kurdish-controlled northern Syria, U.S. forces will sustain the momentum against the Islamic State while protecting America’s Kurdish and Sunni tribal allies from Iranian, Russian, and Syrian aggression.