ISIS reaps gains of U.S. pullout from Syria

American forces and their Kurdish-led partners in Syria had been conducting as many as a dozen counterterrorism missions a day against Islamic State militants, officials said. That has stopped.

Those same partners, the Syrian Democratic Forces, had also been quietly releasing some Islamic State prisoners and incorporating them into their ranks, in part as a way to keep them under watch. That, too, is now in jeopardy.

And across Syria’s porous border with Iraq, Islamic State fighters are conducting a campaign of assassination against local village headmen, in part to intimidate government informants…

News of the American withdrawal set off jubilation among Islamic State supporters on social media and encrypted chat networks. It has lifted the morale of fighters in affiliates as far away as Libya and Nigeria.