Powell v. McCormack

Disagreeing with the court of appeals ruling, the Supreme Court decided that Powell's case was not moot because Powell's back pay was still at issue:

Simply stated, a case is moot when the issues presented are no longer "live" or the parties lack a legally cognizable interest in the outcome . . . Petitioner Powell has not been paid his salary by virtue of an allegedly unconstitutional House resolution. That claim is still unresolved and hotly contested by clearly adverse parties.

Next, the Court had to address the issue of whether it had the right to intervene in what seemed to be an internal House of Representatives issue. The Court resolved this potential violation of the separation of powers by holding that, while Congress has the sole authority to judge the qualifications of its members, it may not add to the qualifications of age, citizenship, and residency spelled out in the Constitution:

Our examination of the relevant historical materials leads us to the conclusion that petitioners are correct and that the Constitution leaves the House without authority to exclude any person, duly elected by his constituents, who meets all the requirements for membership expressly prescribed in the Constitution.