U.S. ConstitutionArticle I — The Legislative BranchSubarticle 8Section 15
To provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions;
Use as reference
Lexinter.net | U.S. Const. art. I, § 8, cl. 15 | https://laws.lexinter.net/constitution/us/article-1/section-8/clause-15