Mootness

Mootness is a doctrine in United States law under which a court will not decide a case where the underlying dispute has been resolved by events, or has otherwise lost any practical significance, so that a ruling would have no real effect. Its constitutional basis lies in the limit that Article Three places on federal judicial power, restricting it to actual cases and controversies, which bars federal courts from issuing decisions on matters that are effectively hypothetical, treating a moot case the way an academic moot-court exercise is treated rather than as live litigation, which is where the term itself comes from. Courts recognize several exceptions to dismissal on mootness grounds, including voluntary cessation of the challenged conduct by a defendant, continuing secondary legal consequences, disputes capable of repetition yet evading review, and class actions where the claim of the named plaintiff becomes moot while the claim of the class survives. British usage of the word moot differs sharply, meaning a question that remains open to debate rather than one that has become legally irrelevant.