Stare Decisis and Precedent

Stare decisis means 'let the decision stand.' When a court rules on a legal question, that ruling becomes precedent: a rule future courts apply when a new case raises the same issue. A lower court judge who personally thinks an old Supreme Court precedent was wrong still applies it, because the system values predictability over any one judge's opinion. People need to know how the law will treat them before they act, and that only works if courts rule consistently rather than reinventing the law case by case.

Precedent builds in chains. One ruling controls similar cases, those cases add detail and get cited themselves, and over time a body of connected decisions grows around the original rule. Courts can distinguish a new case, arguing its facts differ enough that the old precedent does not apply, which is how the chain branches without breaking. A precedent gets overturned only when a court, usually the Supreme Court, decides the earlier reasoning was wrong or no longer fits, and issues a new ruling that replaces it outright.

This is why new appointments matter so much. The Supreme Court is not bound by its own past rulings the way lower courts are bound by the Court's rulings; it can revisit and reverse itself. When appointments shift the Court's ideological balance, settled precedent becomes vulnerable, because a new majority may conclude an old case was wrongly decided and overturn it. That possibility is exactly what connects this topic to the confirmation fights and appointment politics covered elsewhere in this unit: control over who sits on the Court is partly control over which precedents survive.