The Supreme Court of the United States is the highest court in the country and the final authority on what federal law and the Constitution mean. It was created by Article III of the Constitution, sits at the top of the federal judiciary, and its rulings bind every other court in America, state and federal. Only the Court itself, acting in a later case, or a constitutional amendment can undo what it decides.
What the Court Does
Article III vests “the judicial Power of the United States” in “one supreme Court” and whatever lower courts Congress chooses to establish.1Congress.gov. U.S. Constitution – Article III That same section extends the Court’s reach to all cases arising under federal law, the Constitution, and treaties. Congress writes laws and the President enforces them; the Court’s job is to interpret those laws when real disputes reach it.
The Constitution itself says little about how the Court should operate. It does not fix the number of justices, their qualifications, or how they organize their work. Those details were left to Congress and to the Court, which is why the institution has changed so much since its first session in 1790.
Judicial Review
The Court’s most consequential power is not written anywhere in the Constitution’s text. In 1803, Chief Justice John Marshall declared in Marbury v. Madison that the Court has the authority to strike down any law that conflicts with the Constitution.2National Archives. Marbury v. Madison (1803) That principle, known as judicial review, turned the Court from a dispute-resolution body into the final guardian of constitutional limits on government power.
Judicial review applies to both Congress and the President. A federal statute that violates the Constitution can be invalidated. An executive order that exceeds presidential authority can be blocked. This is the core of the checks-and-balances system: the political branches make policy, and the Court polices the constitutional boundaries around that policymaking. The principle has gone unchallenged for more than two centuries.3Justia. Marbury v. Madison
Who Sits on the Court
Federal law sets the Court at nine members: one Chief Justice and eight Associate Justices, with six forming a quorum.4Office of the Law Revision Counsel. 28 USC 1 – Number of Justices; Quorum The number has changed six times in the Court’s history before Congress settled on nine in 1869.5Supreme Court of the United States. The Court as an Institution Every justice has equal voting power. The Chief Justice has additional administrative duties, including presiding over oral arguments and leading the private conferences where cases are discussed.
Justices hold their seats “during good Behaviour,” which in practice means for life or until they choose to retire.1Congress.gov. U.S. Constitution – Article III Lifetime tenure exists to insulate justices from political pressure; a judge who cannot be fired for an unpopular ruling is freer to follow the law rather than public opinion. The only way to remove a sitting justice involuntarily is through impeachment by the House, followed by conviction in the Senate on a two-thirds vote.6U.S. Senate. About Impeachment No Supreme Court justice has ever been removed this way.
How Justices Get There
When a seat opens through death, retirement, or resignation, the President nominates a replacement under Article II, Section 2, which also requires the Senate’s “Advice and Consent.”7Constitution Annotated. Article II Section 2 The Constitution sets no requirements for age, citizenship, legal education, or prior judicial experience. In practice, every justice has been a lawyer, and most have been federal judges, but neither is legally required.
The Senate Judiciary Committee investigates the nominee, holds public hearings, and votes on whether to send the nomination to the full Senate. Confirmation takes a simple majority of senators present. The process can run from a few weeks to several months, and some nominees have been blocked without ever receiving a vote.
What Cases the Court Hears
The Court operates under two kinds of jurisdiction. Original jurisdiction is the rarer type: cases that start at the Supreme Court rather than arriving on appeal. Federal law gives the Court exclusive original jurisdiction over disputes between two or more states, and shared original jurisdiction over cases involving ambassadors or disputes between the federal government and a state.8Office of the Law Revision Counsel. 28 USC 1251 – Original Jurisdiction These cases typically involve boundary lines or water rights.
Nearly all of the Court’s work comes through appellate jurisdiction, reviewing decisions from lower federal courts and from state supreme courts. For state cases, the Court can step in when a case involves the validity of a federal law, a challenge to a state law as unconstitutional, or a claim of rights under the Constitution or federal treaties.9Office of the Law Revision Counsel. 28 USC 1257 – State Courts; Certiorari
The Certiorari Process
Getting the Court to hear your case is extraordinarily difficult. A party seeking review files a petition for a writ of certiorari, a formal request asking the Court to order the lower court to send up the case record.10United States Courts. Supreme Court Procedures The Court has complete discretion over which petitions to accept. Under the Rule of Four, at least four of the nine justices must vote to hear a case before it goes on the calendar.11Legal Information Institute. Certiorari If the petition is denied, the lower court’s decision stands.
The acceptance rate is tiny. In the 2024–25 term, roughly 3,856 petitions were filed, and the Court decided only 56 cases with full briefing and oral argument. The justices focus on cases that present important, unresolved questions of federal law, especially when lower courts have reached conflicting conclusions on the same issue. A garden-variety error by a trial judge, however unjust it feels to the losing party, rarely qualifies.
How a Case Moves Through the Court
Once the Court agrees to hear a case, both sides submit written briefs laying out their legal arguments. Outside parties with a stake in the outcome can also file amicus curiae (“friend of the court”) briefs. Third-party briefs are common in high-profile cases and generally require the written consent of both parties, though the federal government, states, and local governments can file without asking permission.12Legal Information Institute. Supreme Court Rule 37 – Brief for an Amicus Curiae In politically charged cases, the Court sometimes receives dozens.
Oral Argument
After reading the briefs, the justices hear oral argument. Each side gets 30 minutes unless the Court directs otherwise, and requests for extra time are rarely granted.13Legal Information Institute. Supreme Court Rule 28 – Oral Argument The term begins on the first Monday in October and typically runs into late June or early July. Oral arguments are held in two-week “sittings” separated by two-week “recesses” during which the justices research and write opinions. The final sitting for oral arguments usually wraps up in April, with the remaining weeks devoted to issuing decisions.
Argument at the Supreme Court is nothing like a courtroom speech. Lawyers are peppered with questions from the bench almost immediately, and the justices use these exchanges to test the boundaries of each side’s position.
Conference, Opinions, and Mandates
After argument, the justices meet in a private conference where no one else is present. They discuss the case and take a preliminary vote. The Chief Justice, if in the majority, assigns one justice to write the majority opinion. If the Chief Justice is in the minority, the most senior justice in the majority makes the assignment. The majority opinion becomes binding law, setting a legal standard every lower court must follow.14Legal Information Institute. Binding Precedent
Justices who agree with the result but reach it through different reasoning can write concurring opinions. Those who disagree write dissents. Dissents carry no legal force, but they preserve alternative arguments that sometimes gain traction decades later when the Court revisits the issue. All opinions are released to the public. In cases reviewed from a state court, the formal mandate enforcing the decision issues 25 days after the judgment is entered, unless the Court adjusts the timeline or a party files for rehearing.15Legal Information Institute. Supreme Court Rule 45 – Process; Mandates
The Emergency Docket
Not every case follows the full briefing-and-argument track. The Court also handles emergency applications on what is sometimes called the “shadow docket.” These typically involve requests for emergency stays, where a party asks the Court to freeze a lower court’s ruling while the case is being appealed. An individual justice can grant a stay, but the applicant must first show that they sought relief from the lower courts and were denied.16Legal Information Institute. Supreme Court Rule 23 – Stays
Emergency docket orders differ from merits decisions in important ways. They typically come without full briefing or oral argument and often lack detailed written reasoning. The Court may not even disclose which justices voted which way. This has drawn criticism in recent years, particularly when emergency orders have effectively decided major legal questions without the deliberative process that merits cases receive.
Ethics and Recusal
Lower federal judges have been bound by a formal code of conduct since 1973. Supreme Court justices operated without one until November 2023, when the Court adopted its first written Code of Conduct. The code is built around five canons: upholding judicial integrity and independence, avoiding impropriety, performing duties fairly and impartially, limiting extrajudicial activities to those consistent with the judicial role, and refraining from political activity.17Supreme Court of the United States. Code of Conduct for Justices of the Supreme Court of the United States It addresses gifts, outside speaking engagements, teaching, and membership in organizations that discriminate.
Federal law also requires any justice to step aside from a case when their impartiality could reasonably be questioned. Specific grounds for disqualification include personal bias toward a party, prior involvement as a lawyer or witness in the same matter, and financial interests in the outcome held by the justice, their spouse, or a minor child in their household.18Office of the Law Revision Counsel. 28 USC 455 – Disqualification of Justice, Judge, or Magistrate Judge No one can force a justice to recuse. Each justice decides individually whether the statute requires them to sit out, and there is no appeal from that decision.