Overview
Three ideas explain most of American law. It is common law — built on statutes plus a long chain of binding court decisions, or precedent. It is federal — power is divided between one national government and fifty states. And it rests on a single written Constitution that sits above all other law.
Legal system & tradition
The United States inherited the English common-law tradition: law lives not only in written statutes but in the accumulated decisions of courts. Higher-court rulings bind lower courts. Federal and state systems run in parallel; where valid federal law conflicts with state law, federal law prevails under the Constitution’s Supremacy Clause.
Constitution & government
Ratified in 1788 and in force since 1789, the U.S. Constitution is the oldest written national constitution still in use. The first ten amendments — the Bill of Rights (1791) — guarantee core freedoms. Power is split among three branches that check one another.
Courts & disputes
Most disputes are heard in state courts; federal courts handle constitutional questions, federal statutes, and cases that cross state lines. Trial courts find facts, appellate courts review the law, and the Supreme Court of the United States has the final word on federal and constitutional questions.
Major branches of law
Rights & rule of law
Individual rights are protected mainly by the Constitution and its amendments and enforced by independent courts. The Bill of Rights covers speech, religion, assembly, and due process; later amendments extended equal protection and voting rights. Much of their meaning is settled through Supreme Court interpretation.
Key milestones
Higher-risk & getting help
For real decisions, consult a licensed attorney. Free or low-cost help is available through legal aid organisations, public defenders for criminal matters, and state bar referral services. In emergencies involving safety, contact local authorities first.
Official sources
About this profile
JusticeWiki profiles provide general legal orientation, not legal advice. Each section is reviewed and dated, and cites official sources so you can check the original. Found an error? Email us a correction and a reviewer will check it.