Common Law

When most people think of the law, they think of shelves full of dense books containing all the statutes passed by Congress or a state legislature. But is that all that law is?

Many people have heard of common law marriage, a topic that is the subject of many myths and misunderstandings. But what does “common law” mean, anyway? The answer is key to understanding the American legal system.

What is Common Law?

Common law is a term to describe a system where decisions by judges can change the law and impact future cases. It is the system used in the United States federal courts and 49 of the 50 states.

How does Common Law work?

In a common law system, judges make decisions based on statutes and previous judicial decisions in similar cases. These previous decisions are known as “precedent.” In other words, courts are not only bound by laws passed by legislature, but also by previous decisions of higher courts.

This explains why Supreme Court decisions are often prominent in the news. Since the Supreme Court of the United States is the highest court in the country, its decisions impact all lower court decisions in future cases.

Take the famous case Brown v. Board of Education of Topeka (1954) for example. In that case, the Supreme Court declared that the public school district in Topeka, Kansas could not refuse to enroll a local black student. The result of this decision was to make race segregation in public schools illegal all over the country. This example shows the widespread influence courts can have in a common law system.

Why do we use a Common Law system?

Common law originated in England. It is currently the legal system used by England and many former British territories, including the United States. Common law is used in contrast to Civil Law, which is the dominant legal system in Europe and many other parts of the world.

Common Law vs. Civil Law

Unlike in common law, in civil law judges make decisions by interpreting statutes only. Civil law decisions usually do not impact future cases. Civil law has roots in ancient Rome. One popular form of civil law still in use today is the Napoleonic code, which is used by much of Europe and by Louisiana.

For more information about these two systems, see this informative exhibit from Berkeley Law.