caselaw

Caselaw, or case law, is the body of legal rules and principles developed through judicial decisions in courts. In common law systems, caselaw evolves from judicial opinions and serves as a major source of law alongside statutes and regulations; in civil law jurisdictions it generally has persuasive rather than binding force, though it can shape interpretation and application of codes.

Key concepts include the ratio decidendi, the legal rule necessary to decide the case, and obiter dicta, nonessential remarks that may guide future decisions. Precedent binds or persuades future courts depending on jurisdiction and court hierarchy, a principle known as stare decisis.

Caselaw is disseminated through court opinions published in reporters and online databases. Over time, it reflects changes in society and technology and can overrule or distinguish earlier decisions when facts are different or legal theory has evolved.

Judges use caselaw to interpret statutes, fill gaps, resolve disputes about contracts, torts, property, and constitutional issues, and to develop doctrines such as negligence or duty of care. Litigants rely on caselaw to predict outcomes and to argue for or against particular interpretations; lawmakers may respond by amending statutes to overturn or modify precedent.

Limitations of caselaw include potential inconsistencies across jurisdictions, over time leading to conflicting precedents, and slower adaptation to rapid social or technological change. Access to decisions and the complexity of citation also pose challenges for lay readers.