The U.S. Constitution establishes a system of federalism under which the federal government is granted limited authority, with all remaining authority left to the states. This model of shared powers defines the relationship between the federal and state courts. In this overview of the various levels of the U.S. courts, Toni M. Fine, associate director of the Global Law School Program at New York University Law School, explains how the court system functions.

It is something of a myth to speak about a single U.S. court system because the U.S. judicial system is in reality composed of multiple autonomous courts. There is the federal court system, an integrated system divided into numerous geographic units and various levels of hierarchy; in addition, each state has its own court system with a system of local courts that operate within the state. Under this dual federal/state court structure, the U.S. Supreme Court is the final arbiter of federal law, while the highest court of each state (usually called supreme courts) has the ultimate authority to interpret matters of the law of its state. When federal constitutional or statutory matters are involved, the federal courts have the power to decide whether the state law violates federal law.

The functioning of these systems is complicated by the fact that there are multiple sources of law, and courts of one system are often called upon to interpret and apply the laws of another jurisdiction. In addition, more than one court may have sovereignty to hear a particular case.

The federal judiciary and the individual state judicial systems are each constructed like a pyramid. Entry-level courts at both the state and federal levels are trial courts, in which witnesses are called, other evidence is presented and the fact-finder (a jury or sometimes a judge) is called upon to decide issues of fact based on the law.

At the top of each pyramid structure is the court of last resort (at the federal level, the U.S. Supreme Court; at the state level, the state supreme court) which has the authority to interpret the law of that jurisdiction. In most states and in the federal system there is also a mid-level court of appeals.

The vast majority of courts at both the state and federal level are "courts of general jurisdiction," meaning that they have authority to decide cases of many different types. There are no special constitutional courts in the U.S. -- any court has the power to declare a law or action of a government executive to be unconstitutional, subject to review by a higher-level court.

The Federal Courts

Traditional federal courts are known as Article III courts because they have the power of judicial review and certain protections under Article III of the U.S. Constitution. These courts are organized in a three-tiered hierarchical structure and along geographic divisions. At the lowest level are the U.S. District Courts, which are the trial courts. Appeals from the U.S. District Courts are taken to the U.S. Courts of Appeals, often referred to as U.S. Circuit Courts. From there, cases may be brought to the U.S. Supreme Court. Much of the Supreme Court's review power is discretionary, and only a small percentage of cases brought to it are actually ruled on by the Court.

The U.S. District Courts are entry-level courts of general jurisdiction, meaning they hear cases involving various criminal and civil matters. There are 94 U.S. federal judicial districts, with at least one district court in each state. In the largest and most heavily populated states, there are several districts, but districts do not cross state lines. The number of judges depends on the size and population -- and hence workload -- of each district court. Although each district court has numerous judges, a single judge presides over each case.

The U.S. Courts of Appeals, is the intermediate-level federal court. The courts of appeals are considered the workhorse of the federal court system because the brunt of cases are resolved there. Appeals are taken from U.S. district courts to the U.S. courts of appeals if a losing party feels that the judge in the district court made an error of law. Appeals may not be taken to correct perceived errors of fact, unless there is a clear error of law. Thus, for example, a losing party may argue that the judge erred by admitting a certain document into evidence; but the losing party may not argue that the judge or jury reached a bad conclusion based only on that document.

The U.S. Courts of Appeals is divided geographically into 12 circuits -- 11 numbered circuits, each covering at least three states, and the U.S. Court of Appeals for the District of Columbia (D.C. Circuit), which also hears cases involving the federal government. Each circuit hears appeals from the district courts within its territory.

The number of judges in each circuit varies widely and is determined by the population and size of each circuit. A panel of three judges -- chosen at random -- sits on each case, and different combinations of judges sit on different cases.

The U.S. Courts of Appeals may decide cases on the basis of written briefs submitted by the litigants or may order oral argument. A decision is based on written opinion drafted by one of the judges and circulated to the other two panel members. The opinion of the court also must be signed by at least two panel members. Any of the judges on the panel may write a concurring opinion in which the judge agrees with the result reached in the majority opinion but for different or additional reasons. A judge that disagrees with the opinion of the court may instead write a dissenting opinion explaining why he or she has reached a different conclusion. Although dissenting and concurring opinions do not have the force of law, they may be highly influential in subsequent court decisions.

After the three-judge panel has rendered a decision, litigants have several options: they may seek reconsideration of the decision by the same three-judge panel; they may seek rehearing of the panel's decision by all of the judges of that circuit sitting together; or they may seek review by the U.S. Supreme Court by filing a motion for a writ of certiorari, (when the lower courts have ruled on the case and disagreed on their opinions). Each of these measures of relief is discretionary, however, and is rarely granted.

The U.S. Supreme Court is at the apex of the federal court system and consists of nine justices who hear and decide cases. As in the U.S. Courts of Appeals, justices may join the majority opinion or may write or join a concurring or dissenting one.

The Supreme Court's general jurisdiction is largely discretionary through the process of certiorari. Under the so-called rule of four, if four of the nine justices favor hearing a case then certiorari will be granted. The Court often accepts cases in which there is a split of authority among different U.S. circuit courts or in which important constitutional or other legal principles are implicated. The denial of certiorari does not imply agreement with the lower courts' decisions, but simply indicates that the requisite number of justices for whatever reason did not want to hear the case.

Besides a writ of certiorari, the Supreme Court can review cases on appeal from federal courts or state supreme courts whose decisions are based on an issue of federal law (for example, when a federal appeals court invalidates a state statute; or when a state court strikes down a federal statute). The Court also may decide specific legal issues referred to it by lower federal courts.

The Supreme Court also has original jurisdiction over certain limited cases: controversies between two states; controversies between the United States and an individual state; actions by a state against a citizen of another state or an alien; and cases brought by or against a foreign ambassador or consul.

Special Courts

In general, the federal court system does not create special courts for specific matters. Two notable exceptions to this rule are the U.S. Court of Federal Claims, which handles monetary suits brought against the United States, and the U.S. Court of International Trade, which is authorized to hear and decide civil actions against the United States, federal agencies or their employees, arising out of any law pertaining to international trade.

There is also one specialized federal appeals court -- the U.S. Court of Appeals for the Federal Circuit. This court has jurisdiction over appeals from all district courts in cases arising under patent laws as well as over appeals from the U.S. Court of Federal Claims and the Court of International Trade.

The federal system also embraces a number of courts known as legislative or Article I courts, referring to Article I of the U.S. Constitution. Article I courts act pursuant to Congress' legislative powers and have the authority to decide factual questions relating to specific matters. Examples of Article I courts include the U.S. Court of Appeals for the Armed Forces, the U.S. Court of Veterans Appeals, the U.S. Tax Court and the U.S. Bankruptcy Courts. Appeals from these courts may be brought to the U.S. Courts of Appeals.

Administrative Courts

Federal agencies play an enormous role in developing and carrying out U.S. laws on a wide array of topics, from the regulation of natural resources to the health and safety of workers. Often, this means that an agency will sit as a fact-finding tribunal in applying federal regulations. When disagreements occur, the parties present their evidence to an administrative law judge (ALJ), who acts as the fact-finder. Either party may appeal the judge's decision, usually to a board or commission established by the federal agency that issued the regulations. Because the ALJ has already served the fact-finding function that would normally be undertaken by a federal district court, appeals from rulings of major agencies (e.g., National Labor Relations Board or the Federal Trade Commission) are brought directly before the U.S. Courts of Appeals. Although such appeals may be brought in any circuit, as a practical matter the D.C. Circuit hears most appeals from federal agencies.

The State Courts

Each state, as well as the District of Columbia and the Commonwealth of Puerto Rico, has its own independent judicial system, that operates independently. The highest court in each state is the ultimate authority on what the law is with regard to state law from the state's point of view.

The structure of state courts, like that of the federal courts, is in the form of a pyramid. Most states have a three-tiered judicial system composed of a trial-court level (sometimes called superior courts, district courts or circuit courts), an appellate court (often called the court of appeals) and a court of last resort (usually called the supreme court). Some states simply have one level of appeal.

As in the federal court system, trials are presided over by a single judge (often sitting with a jury); entry-level appellate cases are heard by a three-judge panel; and in state supreme courts, cases are heard by all members of the court, which usually number seven or nine justices.

Also like the federal system, state court cases begin at the trial-court level. These courts are often divided into two levels: courts of general jurisdiction and specialized courts.

Cases decided by a trial court are subject to appeal to and review by an appellate court. In some states, as noted above, there is only one level of appeal from the lowest state court. In states in which there are two courts of appeal, rules differ as to whether a case will automatically go to the appeals court or the state supreme court. In some states, appeals from the trial court are brought to the mid-level state appellate court, with subsequent discretionary review by the state supreme court. In other states, litigants bring appeals from the trial-level court directly to the supreme court, which decides whether to hear the case itself or to have the appeal resolved by the intermediate appeals court. Under either of these scenarios, the state supreme court generally reviews cases that involve significant matters of state law or policy.

Specialized state courts are trial-level courts of limited jurisdiction that only hear cases that deal with specific kinds of legal issues or disputes. Although these courts vary from state to state, many states have specialized courts for traffic matters, family law matters, probate for the administration of decedents' estates, and small claims (for cases involving less than a specific sum of money). Rulings of these specialized courts are subject to appeal and review by state courts of general jurisdiction.

Local Courts

Each of the 50 states is divided into localities or municipalities called cities, counties, towns or villages. Local governments, like their state counterparts, have their own court systems, which are presided over by local magistrates, who are public civil officers possessing judicial power delegated under the local governing laws. This may include the power to rule on laws relating to zoning authority, the collection and expenditure of local taxes, or the establishment and operation of public schools.

Conclusion

One of the elements of the U.S. legal system that makes it at once so complex and so interesting is the fact that both the federal government and each state has its own judicial system. Each judicial system is marked by differences in function and operation. Moreover, the fact that there is overlapping jurisdiction and that any court may hear issues of federal and state law complicates the functioning of these systems further. At bottom, all court systems in the United States are similar in most fundamental respects. U.S. courts are, for the most part, courts of general jurisdiction. In addition, each system is in the hierarchical form of a pyramidal structure, allowing review and -- if necessary -- revision by upper-level courts.