23 U.S.C. § 158: National minimum drinking age

The Secretary shall withhold 10 per centum of the amount required to be apportioned to any State under each of sections 104(b)(1), 104(b)(3), and 104(b)(4) 1 of this title on the first day of each fiscal year after the second fiscal year beginning after 1 See References in Text note below. September 30, 1985 , in which the purchase or public possession in such State of any alcoholic beverage by a person who is less than twenty-one years of age is lawful. For fiscal year 2012 and each fiscal year thereafter, the amount to be withheld under this section shall be an amount equal to 8 percent of the amount apportioned to the noncompliant State, as described in subparagraph (A), under paragraphs (1) and (2) of section 104(b). If, before the later of (A) October 1, 1986 , or (B) the tenth day following the last day of the first session the legislature of a State convenes after the date of the enactment of this paragraph, such State has in effect a law which makes unlawful the purchase and public possession in such State of any alcoholic beverage by a person who is less than 21 years of age (other than any person who is 18 years of age or older on the day preceding the effective date of such law and at such time could lawfully purchase or publicly possess any alcoholic beverage in such State), such State shall be deemed to be in compliance with paragraph (1) in each fiscal year in which such law is in effect. No funds withheld under this section from apportionment to any State after September 30, 1988 , shall be available for apportionment to that State. beer as defined in section 5052(a) of the Internal Revenue Code of 1986, wine of not less than one-half of 1 per centum of alcohol by volume, or distilled spirits as defined in section 5002(a)(8) of such Code.