What happens when presidents from more than 100 of the nation's best-known colleges call on lawmakers to consider lowering the drinking age from 21 to 18? Well, a brigade of hyperbolic mommies start screaming at them, that's what. In the Amethyst Initiative, college presidents have offered a rational, if counterintuitive, plan. Let's stop treating young adults like wards of the state. Mothers Against Drunk Driving (naturally) replied: No debate allowed. There is plenty of empirical evidence suggesting that the drinking age of 21 is counterproductive. To begin with, it bars parents from educating their own children about alcohol and, like...