I disagree with professor Max Abrahms and John Glaser of the Cato Institute when they argue that Syrian leader Bashar Assad did not and will not empower the Islamic State.

But they are right about one thing: their sympathy for realism. As they put it, “The realist paradigm reminds us that the U.S. need not share the same ideology of a nasty international actor to countenance working with him against a mutual foe … Realism also emphasizes the dangers of militarily picking foreign governments around the world.”