U.S. Constitution, Article I — The Legislative Branch, Section 6, Clause 2
No Senator or Representative shall, during the Time for which he was elected, be appointed to any civil Office under the Authority of the United States, which shall have been created, or the Emoluments whereof shall have been encreased during such time; and no Person holding any Office under the United States, shall be a Member of either House during his Continuance in Office.
Notes
Bars a Senator or Representative, during the term for which elected, from appointment to any federal civil office created, or whose pay was increased, during that term. Bars anyone holding any office under the United States from being a member of either house while continuing in that office.
Use as reference
Lexinter.net | U.S. Const. art. I, § 6, cl. 2 | https://laws.lexinter.net/constitution/us/article-1/section-6/clause-2