The law of the United States consists of many levels of codified and uncodified forms of law

Law

Law is a system of rules and guidelines which are enforced through social institutions to govern behavior, wherever possible. It shapes politics, economics and society in numerous ways and serves as a social mediator of relations between people. Contract law regulates everything from buying a bus...

, of which the most important is the United States Constitution

United States Constitution

The Constitution of the United States is the supreme law of the United States of America. It is the framework for the organization of the United States government and for the relationship of the federal government with the states, citizens, and all people within the United States.The first three...

, the foundation of the federal government

Federal government of the United States

The federal government of the United States is the national government of the constitutional republic of fifty states that is the United States of America. The federal government comprises three distinct branches of government: a legislative, an executive and a judiciary. These branches and...

 of the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. The Constitution sets out the boundaries of federal law

Federal law

Federal law is the body of law created by the federal government of a country. A federal government is formed when a group of political units, such as states or provinces join together in a federation, surrendering their individual sovereignty and many powers to the central government while...

, which consists of constitutional acts of Congress, constitutional treaties

Treaty

A treaty is an express agreement under international law entered into by actors in international law, namely sovereign states and international organizations. A treaty may also be known as an agreement, protocol, covenant, convention or exchange of letters, among other terms...

 ratified by Congress

United States Congress

The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....

, constitutional regulations promulgated by the executive branch, and case law

Case law

In law, case law is the set of reported judicial decisions of selected appellate courts and other courts of first instance which make new interpretations of the law and, therefore, can be cited as precedents in a process known as stare decisis...

 originating from the federal judiciary

United States federal courts

The United States federal courts make up the judiciary branch of federal government of the United States organized under the United States Constitution and laws of the federal government.-Categories:...

.

The Constitution and federal law are the supreme law of the land

Supremacy Clause

Article VI, Clause 2 of the United States Constitution, known as the Supremacy Clause, establishes the U.S. Constitution, U.S. Treaties, and Federal Statutes as "the supreme law of the land." The text decrees these to be the highest form of law in the U.S...

, thus preempting conflicting state and territorial laws in the fifty U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

s and in the territories.