Article III of the United States Constitution

Article Three of the United States Constitution establishes the judicial branch of the federal government. The judicial branch comprises the Supreme Court of the United States and lower courts as created by Congress.

Section 1 vests the judicial power of the United States in federal courts, requires a supreme court, allows inferior courts, requires good behavior tenure for judges, and prohibits decreasing the salaries of judges.

The judicial Power of the United States, shall be vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish. The 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.

Article III authorizes and sanctions the establishment of (only) one Supreme Court, but does not set the number of justices that must be appointed to it; though Article I, Section 3, Clause 6 refers to a Chief Justice (who shall preside over the impeachment trial of a President). The number of justices is fixed by statute at nine: the one chief justice, and eight associate justices. One associate justice seat is currently vacant.

Proposals to divide the Supreme Court into separate panels have been made, but all have failed. Since all such proposals have failed, the Supreme Court has never ruled on the constitutionality of such a division. However, Chief Justice Charles Evans Hughes wrote, "the Constitution does not appear to authorize two or more Supreme Courts functioning in effect as separate courts."

The Supreme Court is the only federal court that is explicitly mandated by the Constitution. During the Constitutional Convention, a proposal was made for the Supreme Court to be the only federal court, having both original jurisdiction and appellate jurisdiction. This proposal was rejected in favor of the provision that exists today. Under this provision, the Congress may create inferior (i.e., lower) courts under both Article III, Section 1, and Article I, Section 8. The Article III courts, which are also known as "constitutional courts", were first created by the Judiciary Act of 1789. Article I courts, which are also known as "legislative courts", consist of regulatory agencies, such as the United States Tax Court. Article III courts are the only ones with judicial power, and so decisions of regulatory agencies remain subject to review by Article III courts. However, cases not requiring "judicial determination" may come before Article I courts. In the case of Murray's Lessee v. Hoboken Land & Improvement Co. 59 U.S. 272 (1855), the Supreme Court ruled that cases involving "a suit at the common law, or in equity, or admiralty" inherently involve judicial determination and must come before Article III courts. Other cases, such as bankruptcy cases, have been held not to involve judicial determination, and may therefore go before Article I courts. Similarly, several courts in the District of Columbia, which is under the exclusive jurisdiction of the Congress, are Article I courts rather than Article III courts. This article was expressly extended to the United States District Court for the District of Puerto Rico by the U.S. Congress through Federal Law 89-571, 80 Stat. 764, signed by President Lyndon B. Johnson in 1966. This transformed the article IV United States territorial court in Puerto Rico, created in 1900, to an Article III federal judicial district court.

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