Sources of Law


United States Constitution  

Missouri Constitution


Court Decisions

Administrative Regulations and Mo. Supreme Court Rules

Executive Orders

Attorney General's Opinions


The "law" is made up of many different parts having numerous sources. Federal and state constitutions, state and federal statutes, local charters and ordinances, court opinions, administrative rules, regulations and decisions, certain legal opinions and various other legal pronouncements and declarations combine and interrelate to form the body of law that governs our society.

 United States Constitution.  

A.    The U.S. Constitution is the ultimate authority of law in the United States in all matters specified in the Constitution. If its provisions relate to a particular situation involving a state or its citizens, the Constitution controls. (Full text is found in Volume 5, Revised Statutes of Missouri, and in Volume 1 of Vernon's Annotated Missouri Statutes.) A useful Web-based version is at

B.    Constitutional provisions are applied by both state and federal courts and, if necessary, are also interpreted by those courts. The U.S. Supreme Court is the ultimate authority on what the Constitution means, and its decisions must be followed by the state courts.

C.   The U.S. Constitution may be amended by action of three-fourths of the states, either by legislative or convention action (see U.S. Const. Art. V).

Missouri Constitution.

A.   The Missouri Constitution is the ultimate legal authority in the state, subject only to the supremacy of the U.S. Constitution. Statutes that conflict with constitutional provisions will be held invalid by the courts and cannot be enforced. (See Revised Statutes of Missouri, Vol. 5, for full text, and Vernon's Annotated Missouri Statutes, Vols. 1-2, for full text with case annotations.) A useful Web-based version is at

B.    Missouri constitutional provisions are applied and interpreted by both federal and state courts. The Supreme Court of Missouri is the ultimate authority on what the state constitution means.

C.   The state constitution may be amended or revised:

1.     By amendments proposed by the General Assembly.

2.     By constitutional convention.

3.     By the voters through the initiative process. (See sections 116.010-.340, RSMo 2004.)

D.   All amendments must be approved by majority vote of the voters. (See Mo. Const. Art. XII.)


A.    Laws enacted by the United States Congress are found in the United States Code.

1.     Federal laws or statutes deal with those matters of national concern that the U.S. Constitution makes subject to action by Congress. These may be supplemented by state statutes (such as criminal laws and anti-trust laws) so long as the state statutes are not inconsistent with the federal statutes.

2.     In some instances, Congress enacts laws that are intended to "pre-empt" a particular field of law and that are meant to be the entire law in that area. In those cases, the states may not enact laws regulating the same areas. An example is the bankruptcy code.

B.    Laws enacted by the General Assembly of Missouri are found in the Revised Statutes of Missouri (published at least once every 10 years by the Revisor of Statutes, with annual supplements) and (with annotations) in Vernon's Annotated Missouri Statutes (V.A.M.S., published by West Publishing Company, Minneapolis, Minnesota).  The online version of the Revised Statutes of Missouri is updated frequently.

C.   Municipal and county charters and ordinances are usually compiled and maintained by the city or county clerk or some similar official.

1.     Counties of over 85,000 population and certain cities are authorized to adopt charters, which are like local constitutions.

a.     Charters provide more flexibility in structure but are limited by the Missouri Constitution, Article VI, Section 18 (for counties) and Article VI, Section 19 (for cities).

2.     Municipal and county ordinances are enacted by city councils, boards of aldermen, county councils or legislatures, county administrative commissions, etc. Ordinances are effective only within the corporate limits of the city or county where they are enacted.

3.     Statutes, charters and ordinances can be interpreted and applied by court decision.

D.   State and local laws and ordinances can be adopted, amended and repealed by popular vote through the initiative or referendum process (see sections 116.010-.340, RSMo 2004).

 Court Decisions.

A.    Many court decisions involve interpretation or applications of the "common law."

1.     The common law is of English origin. It began in the King's courts and is founded on ancient local rules and customs, which have been molded into legal principles.

a.     The common law migrated to the United States with the first English colonists and has continued to develop in our courts.

b.     To ascertain the principles and rules of the common law, the courts look to the decisions of the English courts and the courts of other states.

c.     Our courts are not bound by the English court decisions or the decisions of other states; these only indicate what the common law has been or is.

2.     Missouri adopted the common law as it existed in English courts prior to 1607 A.D. (Section 1.010, RSMo 2004.)

3.     The common law is the basis for the doctrine of sovereign immunity (the right of the state not to be sued) and of many important tort actions, such as libel and slander, malicious prosecution, actions based on personal negligence, etc.

4.     Though the common law is still important, more reliance is being placed on statutory laws. The common law may be changed or repealed by statute.

B.    Increasingly, court decisions involve interpretation of state and federal statutes, local ordinances, administrative rules and regulations, and the like. Such decisions then become a part of the "body of law" involving the interpreted statutes or rules, and are followed and relied on by other courts and the executive or administrator in applying or carrying out the law.

C.   Court decisions are based on the particular facts of the case before the court. But many cases involve broad legal questions and principles, and a court's decisions may thus have far-reaching effects as precedent on similar cases arising in the future.

D.   Court decisions may result in substantial changes in the statutory law; for example, court decisions have led to changes in death penalty laws, abortion laws, sovereign immunity laws, and tax assessment laws.

E.    In Missouri, circuit court decisions are not published. They do not have a binding effect on any other court, though they might be persuasive with other circuit court judges dealing with similar issues. Decisions of the Court of Appeals are binding on lower courts. (See "Understanding Court Opinions," Handbook Chapter VIII.)

1.     If there are differences between districts of the Court of Appeals, these usually will be resolved by the Supreme Court.

2.     Decisions of the United States District Courts are published but do not establish binding legal precedent. However, they may influence later rulings in the district where decided and perhaps in other districts. Federal Court of Appeals cases, which also are published, are precedent only in the circuit where decided.

 Administrative Regulations and MO. Supreme Court Rules. 

A.    Many local, state and federal regulatory and administrative bodies and agencies are authorized by statute to enact rules and regulations needed to carry out their duties.

B.    Administrative rules and regulations must be published and publicized in accordance with the statutes before they can become effective.

1.     Federal rules and regulations are published in the Federal Register and are compiled in the Code of Federal Regulations.

2.     State rules and regulations are published in the Missouri Register and are compiled in the Code of State Regulations (CSR). (See

C.   Administrative rules and regulations of state agencies are interpreted and applied by the Administrative Hearing Commission and the courts.

D.   The Supreme Court of Missouri establishes rules relating to practice, procedure and pleadings for all courts and administrative tribunals. According to the Missouri Constitution, these rules have the force and effect of laws.

 Executive Orders. 

A.    The chief executive, whether president or governor, can implement statutes or further define executive authority through the use of executive orders, as authorized by the legislative branch.

1.     For example, executive orders have been used to require contractors with the federal government to undertake affirmative action programs.

2.     In Missouri, executive orders have been used to carry out executive branch reorganization plans. The governor does not, however, have a general power to issue executive orders; that authority must be granted by statute.

B.    Executive orders have the force of law and will be applied and enforced unless overturned by legislative or judicial action.

Attorney General's Opinions.

A.    The Missouri Attorney General will issue opinions interpreting certain provisions of law. Such opinions can be obtained only on request of a public official, and are usually limited to narrow questions of interpretation of the statutes.

B.    An Attorney General's opinion is not law nor binding as law, but is generally considered persuasive in the interpretation of a statute. State agencies and officials usually follow such an opinion until it is overruled by the courts.


A.    Though rarely used for this purpose, the treaty power (given to the President by the Constitution, with the right of the Senate to ratify) can be used to create law between nations that will affect United States citizens. Examples are treaties providing for the protection of migratory birds, dealing with fisheries, or limiting the importation or sale of endangered species of animals. (For an important case in this sphere involving the State of Missouri, see


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