Precedent and Stare Decisis

Stare decisis, Latin for to stand by things decided, is the principle that courts should follow earlier rulings on the same legal question. It comes from the English common law tradition and promotes stability, predictability, and equal treatment, since like cases are decided alike. Vertical precedent is strict: lower federal courts must follow Supreme Court decisions and their own circuit's rulings. Horizontal precedent, a court's adherence to its own past decisions, is a strong presumption but not an absolute rule.

The Supreme Court has said stare decisis is weakest for constitutional questions, because only the Court or a constitutional amendment can correct a mistaken constitutional ruling, and strongest for statutory questions, which Congress can fix. In deciding whether to overrule, the Court weighs the quality of the earlier reasoning, whether its rule has proved workable, its consistency with related decisions, later developments, and how much people have relied on it. These factors were applied, and disputed, in Planned Parenthood v. Casey in 1992 and Dobbs v. Jackson Women's Health Organization in 2022.

The Court has overruled its own precedents well over a hundred times. Brown v. Board of Education in 1954 repudiated Plessy v. Ferguson's separate but equal doctrine, West Coast Hotel v. Parrish in 1937 ended the Lochner era of striking down economic regulation, Dobbs overruled Roe v. Wade, and Loper Bright overruled Chevron in 2024. Each overruling is praised by some as correcting error and criticized by others as undermining the Court's legitimacy and the stability of law.