Consequences of Mootness on Appeal

Because federal courts generally only have subject-matter jurisdiction over live controversies, when a case becomes moot during the appellate process, the appropriate first step is a dismissal of the appeal. Mills v. Green, 159 U.S. 651, 653 (1895). In this situation, the appellate court is often called upon to consider whether it should also vacate the lower-court judgment already entered in the case. This decision can have significant consequences for the parties before the court and for future litigants.