Answer:
Supremacy clause
Step-by-step explanation:
If a state's drinking laws allowed eighteen-year-olds to drink alcoholic beverages in violation of the federal government's age requirement of twenty-one, the federal government's age restriction would supersede the state's law based upon the supremacy clause.
The supremacy clause is a provision of an article VI, clause 2 of the united state constitution,this constitution declares the law,constitution and threats of the federal government to be the supreme law of the land to which judges in every state are bound regardless of the contrary state law.