I could drink, legally, during my freshman year of college, but not my sophomore year. Then I was legal again my junior year. Why? Because of the National Minimum Drinking Age Act of 1984. What authority does Congress have to set the drinking age for the states? That’s what South Dakota wanted to know. South Dakota said Congress had no such authority. The U.S. Supreme Court, in a 7-2 decision, disagreed. They upheld the act. We discuss it.