The Arab Spring. The Fall of the Soviet Union. India’s nukes. The U.S. government has a perfectly awful track record of predicting future events. And there’s a good reason why, says the chairman of an influential think tank: it’s friggin’ impossible.

Dr. Richard Danzig, the former Navy Secretary and current chair of the Center For a New American Security (CNAS), has published a comprehensive report on what he convincingly argues is a pretty huge problem for the Pentagon. After all, basing billion-dollar, life-or-death decisions on forecasts practically guaranteed to be wrong isn’t exactly a...