Sources of Law in the United States

Go to the Constitution as a Source of Law

Introducing four sources of law in the United States:


The Constitution

The Constitution is the Supreme Law of the United States and also a source of law.


Statutes are laws enacted by legislative bodies, such as Congress.

Case Law

When judges issue decisions these decisions have the force of law.

Administrative Law

Administrative regulations and decisions, such as those issued by the Securities and Exchange Commission, have the force of law.

The Constitution and the Protection of Important Freedoms

The Constitution is the supreme law of the United States and also a source of law. 

It has two functions.

First, the Constitution organizes the federal government. You may already know that the Constitution replaced the Articles of Confederation to create a stronger national government.  

How does the Constitution organize the federal government?

 The Constitution organizes the federal government by: dividing power between the national government and state governments (federalism); establishing the three branches of the federal government and dividing power among the three branches (separation of powers); and providing each branch of government with powers to limit the powers of the other branches (checks and balances).

Second, the Constitution protects important freedoms.

The Bill of Rights

At the insistence of the anti-federalists, the framers of the Constitution also included Ten Amendments to the Constitution, known as the Bill of Rights.    Anti-federalists demanded the Bill of Rights as a condition to ratifying the Constitution.  They beleived that the Constitution must include express protections for important freedoms.

A bill of rights is what the people are entitled to against every government on earth, general or particular, and what no just government should refuse or rest on inference.  

Thomas Jefferson

Freedoms Protected by the Bill of Rights

The first Eight Amendments of the Bill of Rights protect individual freedoms, such as free speech and the right to be free from unreasonable searches and seizures. The Ninth Amendment establishes that these rights are not all encompassing – – there are other rights that belong to the people. The Tenth Amendment is associated with federalism by reserving powers for the States.

Amendment I

The First Amendment guarantees the right of free speech, freedom of religion, freedom of the press, and the right to assemble.

Amendment II

The Second Amendment protects the right to “keep and bear arms”.  Worded somewhat confusingly, the Supreme Court recently held that the Second Amendment, among other things, guarantees individual rights to possess arms for lawful purposes such as self defense.  

Amendment III

This Amendment prohibits the federal government from housing soldiers in private homes during peacetime.  Although a major issue for 18th century Americans, we are not aware of any litigation concerning this Amendment.

Amendment IV

The Fourth Amendment prohibits unlawful arrests and searches.  The Amendment, among other things, requires an officer to obtain a warrant based upon probable cause before conducting a search.  Evidence seized in violation of the Fourth Amendment may be subject to the exclusionary rule.   

There are circumstances where courts do not require officers to obtain a warrant,  such as where a police officer searches a defendant following an arrest.

Amendment V

The Fifth Amendment requires the federal government to indict someone by a grand jury before  charging him with a serious crime.  In addition, the Fifth Amendment prohibits “double jeopardy,” meaning a person cannot be tried twice for the same crime in the same jurisdiction.

The Fifth Amendment also prohibits the government from depriving a person of “life, liberty, and property without due process of law.” This is the so-called Due Process Clause of the Fifth Amendment and derives from the English Magna Carta.   Pursuant to the Due Process Clause, the government must provide fair procedures before punishing someone or taking his property.  The Fifth Amendment also provides people with the right to remain silent  at trial and against self incrimination when questioned by the police.  The Fifth Amendment protection against self-incrimination is the basis for so-called Miranda warnings.


Amendment VI

This Amendment guarantees criminal defendants the right to a speedy trial by jury, the right to confront (cross-examine) witnesses, and the right to counsel



Amendment VII

The Seventh Amendment provides that in civil “common law” cases a person has the right to a trial by jury.  This Amendment does not apply to certain types of cases, sometimes called cases in equity.



Amendment VIII

This Amendment prohibits excessive bail and also prohibits “cruel and unusual” punishment.

Recently, the Supreme Court found that the Eighth Amendment prohibits both capital punishment for juveniles and life imprisonment without the possibility of parole for juveniles.



Amendment IX

One objection to the Bill of Rights was that by identifying certain rights as protected, other freedoms were apparently left unprotected from interference by the federal government.  The Ninth Amendment addresses this concern by stating that rights which belong to the people cannot be taken away by the government even if those rights are not included in the Bill of Rights.



Amendment X

The Tenth Amendment declares that powers which do not exclusively  belong to the federal government belong to the states.


Incorporation of the Bill of Rights

The Bill of Rights only explicitly refers to the federal government.  But what about state governments?

Are state governments required to protect all the freedoms of the Bill of Rights?

In a series of decisions, the Supreme Court of the United States found that the 14th Amendment of the United States Constitution incorporates – – applies – –  many of the rights in the Bill of Rights against the states.

Do the Bill of Rights Apply to the States?

The First Amendment begins, “Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof . . .”  So Congress cannot interfere with the freedom of religion, deny people freedom of speech, etc.  But may a state government require people to attend a church or prohibit people from criticizing the government?   

Among other things, the Due Process Clause of the 14th Amendment provides that states may not deprive a person of life, liberty, or property without due process of law.

The wording of the due process clause in the Fourteenth Amendment mirrors the wording of the due process clause in the Fifth Amendment.   When a state allegedly violates a person’s right to due process, the person deprived of due process may argue that the state’s action is unconstitutional because it violated the Fourteenth Amendment.   According to the Supreme Court, the Due Process Clause takes rights in the Bill of Rights and applies these rights against the states.

By way of example, in the 1925 decision Gitlow v. New York, the Supreme Court found the First Amendment right to free speech is among the liberties protected by the 14th Amendment’s Due Process Clause. According to the Supreme Court, just as the federal government may not deny someone his constitutional right to free speech, states also may not deprive a person of his right to free speech.

In the decades since 1925, the Supreme Court has found  that most of the rights in the Bill of Rights are incorporated by the Fourteenth Amendment against the states.  Most, but not all.  For example, the Fifth Amendment right to a grand jury has not been incorporated against the states.  For that reason, some states do not have grand juries or only use grand juries in certain cases.

You may hear an attorney claim that a state violated his client’s “First Amendment right to freedom of speech as incorporated against the states by the Fourteenth Amendment.”  The attorney is speaking precisely.  The state violated his client’s right to freedom of speech as guaranteed by the First Amendment but the First Amendment applies against the state because of the 14th Amendment.