After a decade of unfathomable violence and human tragedy that has made Syria the defining war of the early 21st century, the fighting has tapered off but the suffering hasn’t. In 2011, Bashar Assad and his government briefly looked like another domino about to fall in the whirlwind of pro-democracy revolts sweeping the Middle East. Ten years later, Assad is still there, a pyrrhic victor offering no credible prospects of ...