In the 1968 case of Powell v. McCormack, Adam Clayton Powell Jr., a duly elected member of the House of Representatives from New York, was excluded from his seat by a vote in Congress due to allegations of financial misconduct and defamation against him. The Supreme Court ruled that the House had overstepped its constitutional authority by excluding Powell because he met all constitutionally specified requirements for membership - age, citizenship and residency in his represented state. The court held that while Article I Section 5 gives each house power to judge qualifications of its members, it does not allow either body to develop additional qualifications beyond those stated in the Constitution itself. Therefore, since Powell met all constitutional requirements for office at time when he was seated (and thus could not be denied his seat), any disciplinary action needed would have been expulsion which requires two-thirds majority vote rather than simple majority used for exclusion.

In the dissenting opinion for Powell v. McCormack, Justice John Marshall Harlan II argued that the case was non-justiciable, meaning it should not have been decided by a court of law. He believed that the Constitution granted each House of Congress exclusive power to judge its members' qualifications and thus, it was inappropriate for courts to interfere in this process. The majority's decision to intervene represented an overreach into legislative affairs which could potentially undermine separation of powers principles fundamental to American democracy. Furthermore, he contended that even if judicial review were appropriate in such cases, Adam Clayton Powell Jr., who had been excluded from his seat in Congress despite meeting constitutional requirements for office-holding as per Article I Section 5 Clause 1 , still would not be entitled to relief because he failed to exhaust all available remedies within the House before seeking judicial intervention.