U.S. ConstitutionArticle II — The Executive BranchSubarticle 1Section 4
The Congress may determine the Time of chusing the Electors, and the Day on which they shall give their Votes; which Day shall be the same throughout the United States.
Use as reference
Lexinter.net | U.S. Const. art. II, § 1, cl. 4 | https://laws.lexinter.net/constitution/us/article-2/section-1/clause-4