A case is moot when the issues presented are no longer "live" or the parties lack a legally cognizable interest in the outcome. Where one of the several issues presented becomes moot, the remaining live issues supply the constitutional requirement of a case or controversy.
Petitioner challenged the U.S. House of Representatives' refusal to allow him to take his seat in the 90th Congress by voting to expel him by a two-thirds vote after the 89th Congress found him guilty of filing deceptive travel expense reports and making illegal salary payments to his wife. The parties agreed that petitioner met the standing qualifications for election to Congress set forth in U.S. Const. art. I, § 2. While the case was pending in the Supreme Court, the 90th Congress ended and Powell was elected to and seated by the 91st Congress. Respondents contend that the case is moot.
Was the case of petitioner mooted by his seating in the 91st Congress?
The case has not been mooted by Powell's seating in the 91st Congress, since his claim for back salary remains a viable issue — (a) Powell's averments as to declaratory relief are sufficient; (b) The mootness of Powell's claim to a seat in the 90th Congress does not affect the viability of his back salary claim with respect to the term for which he was excluded.