Who’s right: Cassandra or Dr. Pangloss? Are we on the brink of serious trouble, as Cassandra of Greek myth prophesied, or is all for the best “in this best of all possible worlds,” as the fictional Pangloss insisted in Voltaire’s Candide? “I’m generally a fairly upbeat guy, despite my realist proclivities and my recurring frustrations at the embarrassing state of U.S. foreign policy,” Stephen M. Walt writes in Foreign Policy. “But today I’m going to indulge my inner Cassandra and describe the five bad things that worry me today. I hope I’m wrong.”