The United States Supreme Court has held that the withholding of federal highway funds from states that failed to comply with a congressional directive establishing twenty-one as the states' minimum age for alcohol consumption and purchase is a valid exercise of the spending power.
South Dakota v. Dole, 107 S. Ct. 2793 (1987).
Jeffrey L. Love,
Constitutional Law - Spending Clause - Twenty-First Amendment,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol26/iss4/10