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 Behaviour, and shall, at stated Times, receive for their Services, a Compensation, which shall not be diminished during their Continuance in Office.
Here the Constitution creates only the Supreme Court, granting it all "the judicial power of the United States." Thus the Supreme Court is the head of the judicial branch, just as the president is the head of the executive branch. This clause also gives Congress the power to create "inferior courts"—that is, lower-level federal courts that can serve under the Supreme Court to help the Supremes work though the federal caseload. In practice, over 200+ years of American history, Congress has passed laws establishing a large federal judiciary, comprising nearly 100 federal district courts, a dozen circuit Courts of Appeals, and several other types of special courts. Federal judges are appointed for life terms, and are paid salaries that cannot be cut during the time they remain on the bench.