South Dakota v. Dole,
483 U.S. 203 (1987)
Congress, determining that states with lower minimum drinking ages created incentives for young people to drink and drive, decided to withhold a percentage of otherwise available federal highway funding from states that allowed persons under twenty-one to purchase alcohol. South Dakota brought suit against the United States secretary of transportation.
Held: Even if Congress, in view of the Twenty-first Amendment, might lack the power to impose directly a national minimum drinking age (a question not decided here), 158's indirect encouragement of state action to obtain uniformity in the States' drinking ages is a valid use of the spending power.