Constitution of the United States-Article IV
Section 1. Full faith and credit shall be given in each state to the public acts, records, and judicial proceedings of every other state. And the Congress may by general laws prescribe the manner in which such acts, records, and proceedings shall be proved, and the effect thereof.
Section 2. The citizens of each state shall be entitled to all privileges and immunities of citizens in the several states.
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Was federal legislation required in order for Missouri to accept a driver’s license from a citizen of Vermont?
--here's what covers drivers licenses--
-- http://www.aamva.org/KnowledgeCenter/Driver/Compacts/Driver+License+Agreement+%28DLA%29.htm