Standing asks whether the plaintiff is entitled to have a court decide the merits of the dispute. In federal court it is constitutional and jurisdictional, which means it can be raised at any stage — including on appeal, and by the court on its own.

Three elements. An injury in fact that is concrete and particularized and actual or imminent rather than conjectural; causation, in that the injury is fairly traceable to the challenged conduct; and redressability, in that a favorable decision is likely to remedy it.

What fails. A generalized grievance shared with the public at large. An injury that is speculative or contingent on independent choices by third parties. And a plaintiff seeking prospective relief who cannot show a real and immediate threat of future harm, as distinct from past injury — which is why a claim for damages may proceed while an injunction claim on the same facts does not.

Related doctrines dispose of cases on similar grounds: ripeness, where the dispute has not yet matured; mootness, where it has ended; and political question, where the issue is committed to another branch.

Organizational and associational standing allow entities to sue on their own injuries or on behalf of members in defined circumstances, and are frequently the route where individual injuries are diffuse.