National Minimum Drinking Age Act (1984)
Congress passed a law withholding a portion of federal highway funds from states that did not set 21 as the minimum drinking age. The penalty started at 5% of highway funds and rose to 10%.
All 50 states and the District of Columbia raised their drinking ages to 21 by 1988.
Established the model of using federal transportation dollars to push social policy; the law remains in effect.
Shows a durable precedent for conditioning federal transportation funding on social policy goals unrelated to roads or transit.
