The Supreme Court of the United States has held that Congress, in judging the qualifications of its members, is limited to the standing qualifications prescribed by the Constitution.
Powell v. McCormack, 89 S. Ct. 1944 (1969).
Elmer S. Beatty,
Constitutional Law - Qualifications of Congressmen,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol8/iss1/19