Spies gather intelligence, but someone still has to decide—usually without certainty. From the Prussian war game to the Catholic Church's Devil's Advocate, Israel's "Tenth Man," and the red teams that stress-tested the bin Laden raid, history shows that the most dangerous moment in any investigation isn't when the file is thin and everyone's arguing. It's when the file feels complete and everyone agrees. Are you red teaming your case—or one unchallenged assumption from disast