Traci Toomey, a professor at the University of Minnesota School of Public Health who has studied the numbers, said setting the drinking age at 21 “has been one of the most successful alcohol control policies we’ve had in the U.S. When the drinking age was lowered [in many states in the 1970s and 1980s,] that led to more consumption and traffic crashes.”

According to the National Highway Traffic Safety Administration, between 1982 and 1998 there was a 61 precent drop in young drivers killed in car accidents in which alcohol was involved, even as the number of deaths among nondrinking teen drivers slightly increased.

Yet, the law hasn’t really budged the number of binge drinkers, said Barrett Seaman, director of Choose Responsibility, a nonprofit group, and author of “Binge: What Your College Student Won’t Tell You.”