About 40 million Americans have stopped going to church in the past 25 years. “That’s something like 12 percent of the population, and it represents the largest concentrated change in church attendance in American history,” he writes. The Great Dechurching, a forthcoming book analyzing surveys of more than 7,000 Americans conducted by two political scientists, attempts to figure out why so many Americans have left churches in recent years. The book suggests that the defining problem driving out most people who leave is … just how American life works in the 21st century. Contemporary America simply isn’t set up to...