What is the role of the United States Supreme Court?

The Supreme Court of the United States is the "highest" court in the land. It has ultimate authority to hear appeals in nearly all cases decided in the federal court system. It can also hear certain "appeals" from state high appellate courts that involve a "federal question," such as an issue involving a federal statute or arising under the Constitution of the United States. However, fewer than 100 cases are actually heard and decided by the Supreme Court in one year.

There are currently 9 justices on the Supreme Court: one chief justice and eight associate justices. The number of justices is set by congress and the actual justices are nominated by the president. As of 2010, John G. Roberts Jr. is the Chief Justice. The main conditions for them to hold office is found in Article III Section 1 of the Constitution, “[t]he Judges, both of the supreme and inferior Courts, shall hold their Offices during good Behavior, and shall, at stated Times, receive for their Services, a Compensation, which shall not be diminished during their Continuance in Office.” 

According to Article II Section 2 of the United States Constitution, the Supreme Court has the following power: “The judicial Power shall extend to all Cases, in Law and Equity, arising under this Constitution, the Laws of the United States, and Treaties made, or which shall be made, under their Authority;-to all Cases affecting Ambassadors, other public Ministers and Consuls;-to all Cases of admiralty and maritime Jurisdiction;-to Controversies to which the United States shall be a Party;-to Controversies between two or more States;—between a State and Citizens of another State;-between Citizens of different States;—between Citizens of the same State claiming Lands under Grants of different States, and between a State, or the Citizens thereof, and foreign States, Citizens or Subjects.”