Article I, Section 5 of the Constitution gives the House and Senate each the sole power to "be the Judge of the Elections, Returns and Qualifications of its own Members." But how far does that power go? In 1967, the House voted to exclude Adam Clayton Powell Jr., a Black congressman from Harlem, after a committee found he had misused public funds. Powell met every constitutional qualification -- he was over 25, a U.S. citizen for more than seven years, and a resident of New York -- but the House barred him anyway. The Supreme Court ruled in Powell v. McCormack (1969) that Congress can't add qualifications beyond those listed in the Constitution. The Court drew a sharp line: Congress can refuse to seat someone who fails the age, citizenship, or residency requirements, but for anything else it must use its expulsion power, which demands a two-thirds vote. That distinction matters. In all of American history, only 21 members have been expelled -- 17 for supporting the Confederacy, and most recently George Santos in December 2023. The two-thirds threshold makes expulsion deliberately difficult, protecting elected representatives from being ousted by a simple majority of political rivals.