Common law

Common law, also known as case law or precedent law, is a legal system in which judicial decisions from prior cases serve as binding authority for future disputes, founded on the principle of stare decisis (to stand by things decided). Originating in medieval England, it has evolved into a cornerstone of the legal frameworks in the United States, Canada, Australia, India, and many other jurisdictions that formerly belonged to the British Empire.

Origins and historical development

Common law traces its roots to the unification of English law after the Norman Conquest of 1066. Royal courts began travelling the country to hear disputes, gradually replacing the fragmented local customs with a uniform, "common" body of law. The emergence of the doctrine of precedent in the 12th and 13th centuries, alongside the development of the writ system, allowed judges to compile decisions in Year Books and subsequent law reports. Over time, the common law was supplemented and sometimes supplanted by equity, a separate body of law developed by the Court of Chancery to address rigidities in the common law system. The Judicature Acts of 1873–1875 merged common law and equity courts in England, establishing the modern administration of both.

Core characteristics

Stare decisis and precedent

The doctrine of stare decisis is the defining feature of common law. Lower courts must follow the decisions of higher courts in the same jurisdiction on similar facts; appellate courts generally respect their own prior rulings unless there is a compelling reason to overturn them. This principle creates predictability, consistency, and stability in the law, while allowing gradual evolution through judicial interpretation.

Judge-made law

Unlike civil law systems that rely primarily on comprehensive codes enacted by legislatures, common law grants judges a significant role in law creation. When no statute governs a dispute, a court's decision—including the reasoning (ratio decidendi)—becomes binding precedent for future litigants. Even in the presence of a statute, courts often interpret and refine legislative meaning through case law.

Adversarial system

Common law countries typically employ an adversarial procedural system, where two opposing parties present evidence and arguments before an impartial judge or jury. The judge acts as a neutral referee, and the jury (in many cases) determines facts, with the judge deciding questions of law. This contrasts with the inquisitorial system common in civil law jurisdictions.

Relationship with statutes

While common law is judge-made, legislative statutes take precedence over case law. A parliament or congress can override or modify common law rules by enacting new legislation. In practice, statutes often codify or clarify principles that previously existed only in case law. When a statute covers a field, courts interpret it according to established canons of construction, but the common law continues to fill gaps and interpret ambiguous provisions.

Common law jurisdictions

Common law systems prevail in the United Kingdom (except Scotland, which retains a mixed system), Ireland, the United States (except Louisiana, which has a civil law heritage), Canada (except Quebec), Australia, New Zealand, India, Pakistan, Nigeria, Singapore, Hong Kong (as a special administrative region of China), and many other Commonwealth nations. Some countries, such as South Africa and Sri Lanka, have mixed legal systems combining common law and civil law elements.

Modern developments and critiques

In the 20th and 21st centuries, common law systems have witnessed increased reliance on legislation, administrative regulations, and codification. The United States, for example, has codified large areas of commercial law through the Uniform Commercial Code. Critics argue that the complexity and volume of case law can overwhelm litigants and that the doctrine of precedent may entrench outdated rules. Proponents counter that the system’s flexibility and incremental reasoning allow it to adapt to changing social conditions without radical disruption. The global spread of common law through colonization and economic influence has made it one of the world’s two dominant legal traditions, alongside civil law.