In the 1980's, the federal government compelled the states to raise their drinking age by

By the end of the 1970s and the early part of the 1980s, the federal government once again became concerned about the minimum legal drinking age within each state. The government knew that an amendment to the US Constitution would likely not work because of the past so the federal government came up with an even cleverer way to raise the national minimum drinking age through the use of an "unfunded federal mandate."

Interpreting the results of his experiment : )