Article III
The third article of the U.S. Constitution, which establishes the judicial branch. It vests judicial power in one Supreme Court and any inferior courts Congress may establish, defines the scope of federal jurisdiction, and guarantees the right to a jury trial in criminal cases.
Article III establishes “one supreme Court” and gives Congress the power to create lower federal courts as needed — Congress used this authority almost immediately with the Judiciary Act of 1789, creating the federal district and circuit court system that, with modifications, still exists today. Article III judges, unlike many other federal officials, serve “during good Behaviour,” which functions as life tenure since the only removal mechanism is impeachment; their salaries also cannot be reduced while in office, a deliberate insulation from political pressure.
Article III also limits federal courts to deciding actual “Cases” and “Controversies” — a real, concrete dispute between parties with a personal stake in the outcome, not a hypothetical or advisory question. This requirement is why federal courts have developed doctrines like standing (a party must show real, personal injury) and mootness (a live dispute must still exist) to screen out cases that don’t fit the constitutional definition of a genuine controversy.
Common misconception: people often assume any sufficiently important legal question can be brought straight to federal court for a ruling, similar to asking a legislature to weigh in on a policy debate. Federal courts under Article III can only decide genuine, concrete disputes between parties with something real at stake — they have no general power to issue advisory opinions on abstract legal questions, no matter how significant those questions might be.