Glossary
Standing
The requirement that a plaintiff has a personal stake in the outcome of a case: typically requiring an actual injury, caused by the defendant, that a court can remedy. Without standing, a court has no power to hear the case.
Standing prevents people from suing over things that didn't actually harm them. You generally can't sue because you disagree with a government policy in the abstract: you have to show that the policy hurt you specifically.
The federal-court standing test usually requires three things: (1) a concrete and particularized injury, (2) caused by the defendant's conduct, (3) that the court can redress with a favorable ruling. State court standing requirements vary.
Standing can be raised at any time: like other jurisdictional defects, courts can (and must) dismiss for lack of standing even if no one mentions it.