How is the idea of precedent related to the idea of stare decisis?

Answer 1

Stare decisis (Latin: maintain what has been decided) is a common law legal principle that encourages courts to makes decisions based on established interpretations of statutes or the Constitution set in earlier cases, called precedents.

Precedents set by higher courts, such as the US Supreme Court, are binding, meaning inferior trial and appellate courts are supposed to use them as rules for deciding similar cases. This helps maintain consistency in applying the law.

While the Supreme Court often maintains precedents established by earlier (Supreme) Courts, they have the authority to overturn old precedents and set new ones when appropriate. One well-known example is when the Warren Court decided segregation was unconstitutional in Brown v. Board of Education, (1954). This overturned a precedent known as the "separate but equal" doctrine affirmed in Plessy v. Ferguson, (1896) that declared providing separate facilities for African-Americans and Caucasians was constitutional, as long as the facilities were of equal quality (which was seldom the case). The old precedent was overturned when the Supreme Court reinterpreted the Fourteenth Amendment Equal Protection Clause and determined that "separate but equal" was never equal because segregating African-Americans was comparable to labeling them inferior, and was therefore unconstitutional.

For more information, see Related Questions, below.

Answer 2

In common law jurisdictions, precedent is official (i.e. published) case law occurring prior in time to an issue at hand. The doctrine of stare decisis states that all precedent should be respected (i.e. not overturned or avoided), unless good reason calls for departure. Good reason varies - changed culture, different facts, different social/political/economic environment, etc. - but the doctrine at least makes it hard to depart from prior case law without cause.

Example: In a common law jurisdiction where Penal Code X forbids crossing streets at night, a 1950 case states that PCX does not apply to one-footed left-handed people. This 1950 case is never overturned.

When, in 2012, then the next case comes charging a one-footed left-handed person crossing a street at night with violating Statute X, the 1950 case is precedent for this set of facts. The doctrine of stare decisis should operate to ensure that the 2012 defendant gets an acquittal or dismissal, all things equal.

Answer 3

Because stare decisis is the principle of following judicial precedent