Article I, Section 8, Clause 18:
[The Congress shall have Power . . .] To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof.
No provision of the Constitution expressly authorizes either house of Congress to make investigations and exact testimony to the end that it may exercise its legislative functions effectively and advisedly. But such a power had been frequently exercised by the British Parliament and by the Assemblies of the American Colonies prior to the adoption of the Constitution.1 It was asserted by the House of Representatives as early as 1792 when it appointed a committee to investigate the defeat of General St. Clair and his army by Native Americans in the Northwest and empowered it to
call for such persons, papers, and records, as may be necessary to assist their inquiries.2