The powers granted to the Supreme Court come from two sources: Article III of the Constitution, which sets out the Court’s jurisdiction, and the Court’s own 1803 decision in Marbury v. Madison, which claimed the authority to strike down laws as unconstitutional. Working from those two foundations, the Court interprets federal statutes and the Constitution, hears a small set of cases as a trial court, reviews appeals from lower federal and state courts, issues emergency orders, sets binding precedent for every other court in the country, and writes the procedural rules that govern federal litigation. It holds all of this authority without any direct ability to enforce what it decides.
Where the Powers Come From
Article III, Section 2 defines “the judicial Power” of the United States. It reaches cases arising under the Constitution, federal statutes, and treaties, along with disputes involving ambassadors, admiralty matters, and controversies where the United States or a state is a party.1Constitution Annotated. Article III Section 2 That same clause splits the Court’s work into two tracks: original jurisdiction for a narrow set of cases, and appellate jurisdiction over everything else, subject to exceptions Congress may create.
Built into Article III is a hard constraint. Federal courts can only hear actual “cases” and “controversies,” which the Court has long read to mean it cannot issue advisory opinions or answer hypothetical legal questions.2Constitution Annotated. Overview of Advisory Opinions Someone must have a real stake in a live dispute before the justices will get involved. Early presidents asked the Court for legal guidance on policy questions and were turned down, and the rule still holds. The Court is reactive by design. It cannot go looking for laws to evaluate.
Judicial Review
The single most consequential power the Court holds is judicial review: the authority to examine acts of Congress or the President and declare them unconstitutional. The Constitution never mentions this power. Chief Justice John Marshall asserted it in Marbury v. Madison in 1803, holding that a provision of the Judiciary Act of 1789 was unconstitutional because it attempted to expand the Court’s original jurisdiction beyond what Article III allowed.3Justia Law. Marbury v. Madison, 5 U.S. 137 (1803) Marshall wrote that “it is emphatically the province and duty of the Judicial Department to say what the law is.” Any law conflicting with the Constitution, under that principle, is void.
Striking down a law does not always mean invalidating the entire statute. Under the severability doctrine, the Court can remove the unconstitutional piece and leave the rest intact, so long as the remaining provisions can function on their own and doing so aligns with what Congress intended. The survival of large legislative packages sometimes turns on whether a single problematic section can be cut away.
Interpreting Federal Law and the Constitution
Judicial review gets the attention, but the Court’s day-to-day influence comes from interpretation: deciding what a law actually means. Federal statutes often use broad or ambiguous language. A law might regulate activities that “substantially affect” interstate commerce without defining how much effect counts. When people disagree over what language like that reaches, the Court’s reading becomes the authoritative one.
Interpretation and judicial review are not the same tool. Judicial review asks whether a law is permissible under the Constitution. Interpretation asks what a permissible law requires or prohibits. The consequences differ. A constitutional ruling is effectively permanent, undone only by a later Court reversing itself or by a constitutional amendment. A statutory interpretation can be answered by Congress rewriting the law, and that back-and-forth happens regularly.
After deciding a case, the Court often sends it back to a lower court through a process called remand, with instructions to reconsider the dispute under the Court’s new interpretation. The lower court then applies the ruling to the specific facts of the case.
Original Jurisdiction
In a small number of cases, the Court acts as a trial court, hearing a dispute from the beginning rather than reviewing a lower-court decision. Article III grants this original jurisdiction over cases involving ambassadors and other foreign diplomats, and over disputes where a state is a party.1Constitution Annotated. Article III Section 2 Congress cannot expand or contract this grant; it is fixed by the Constitution.
Federal statute organizes the authority further. The Court has exclusive jurisdiction over lawsuits between two or more states, meaning no other court can hear those disputes.4Office of the Law Revision Counsel. 28 U.S.C. 1251 – Original Jurisdiction For other original jurisdiction categories, including cases involving diplomats and suits by a state against citizens of another state, the Court’s jurisdiction is original but not exclusive, so those cases can also be heard in lower federal courts.
These cases are rare, and nine justices are not set up to hear live testimony and sift through evidence. When a border or water-rights dispute between states arrives, the justices typically appoint a special master, a legal expert who gathers evidence, hears witnesses, and produces a report with recommendations. The Court then reviews that report and issues a final ruling. Complex interstate disputes handled this way can stretch over years.
Appellate Jurisdiction
Nearly all of the Court’s work arrives through appellate jurisdiction, the power to review decisions from lower courts. Appeals come from the federal circuit courts and from state supreme courts when the case involves a federal constitutional or statutory question.1Constitution Annotated. Article III Section 2 Article III expressly allows Congress to make “Exceptions” and “Regulations” governing this appellate power, and Congress has used that authority aggressively.
The most important example is the Judiciary Act of 1925, often called the Judges’ Bill. Before 1925 the Court was required to hear a large volume of appeals and was drowning in its caseload. The 1925 act stripped most of that mandatory jurisdiction and replaced it with discretionary review through the writ of certiorari.5Federal Judicial Center. Landmark Legislation: The Judges’ Bill From that point on, the justices could choose which cases to hear.
Today the Court receives roughly 7,000 to 8,000 certiorari petitions a year and hears oral argument in about 70 to 80.6Supreme Court of the United States. Oral Arguments Selection follows the Rule of Four: at least four of the nine justices must vote to accept a case before the Court will hear it. Review tends to be granted when lower courts have reached conflicting conclusions on the same legal question, when a case raises a significant constitutional issue, or when a lower court’s decision conflicts with Supreme Court precedent. A denial of certiorari does not mean the Court agrees with the lower court. It means fewer than four justices saw a reason to take the case.
A narrow category of mandatory appeals still exists. The Court must hear direct appeals from three-judge district court panels that grant or deny injunctions in cases where Congress has specifically required that three-judge format.7Office of the Law Revision Counsel. 28 U.S.C. 1253 – Direct Appeals From Decisions of Three-Judge Courts These often involve redistricting and voting-rights challenges, and they bypass the circuit courts entirely.
Emergency Orders
Alongside its argued cases, the Court handles a fast-moving stream of emergency applications. These are requests to block or preserve a lower-court ruling while litigation continues, and the docket has grown significantly in recent years under the informal label “shadow docket.”
Emergency applications land first with a single justice, the circuit justice, assigned to the geographic area where the case originated. That justice can grant or deny the request alone or refer it to the full Court. The timelines are compressed, sometimes to days or hours. Unlike cases chosen for full briefing and oral argument, emergency orders are usually brief, often unsigned, and issued without the detailed reasoning found in standard opinions. During the October 2024 term, the Court handled over 100 emergency-docket matters alongside the cases it decided after oral argument.
The practical reach of these orders is wide. A single emergency stay can determine whether an election law takes effect, whether an execution proceeds, or whether a regulation applies to millions of people, all before the underlying legal dispute is resolved.
Authority Over Other Courts
The Court shapes the behavior of every other court in the country through two mechanisms: binding precedent and rulemaking.
Binding Precedent
When the Court decides a case, its holding becomes binding precedent under the doctrine of stare decisis, Latin for “to stand by things decided.” Every lower federal court, and every state court addressing a question of federal law, must follow that ruling in similar future cases. A single Supreme Court opinion can change the law nationwide overnight. The doctrine promotes consistency and predictability, letting people and businesses arrange their affairs around settled rules.
Stare decisis is not absolute. The Court can overrule its own prior decisions, though it treats that step as serious and relatively rare. When it does reverse itself, the effects move through the entire legal system as lower courts adjust.
Rulemaking and Supervisory Power
Federal courts hold inherent power to oversee the conduct of attorneys, parties, witnesses, and jurors to protect the orderly administration of justice.8Constitution Annotated. Inherent Powers Over Judicial Procedure The Supreme Court has used this supervisory authority to police federal law-enforcement practices and to set standards for how federal criminal proceedings are run.
Congress has also given the Court a legislative-style power. Under the Rules Enabling Act, the Supreme Court prescribes the Federal Rules of Civil Procedure, Criminal Procedure, and Evidence for all district courts and courts of appeals.9Office of the Law Revision Counsel. 28 U.S.C. 2072 – Rules of Procedure and Evidence These rules cannot change anyone’s legal rights; they govern process, not substance. Any existing federal law that conflicts with a new rule loses its force once the rule takes effect.
What the Court Cannot Do
For all its reach, the Court’s authority has real limits.
No Enforcement
The Court has no army, no police force, and no independent way to make anyone comply with its decisions. It depends on the executive branch to enforce its rulings, and whether the executive is actually obligated to do so has never been definitively settled. Compliance has historically rested on a shared belief in the rule of law rather than any enforcement mechanism. After the Court ruled in Worcester v. Georgia (1832) that Georgia could not impose its laws on Cherokee territory, Georgia’s governor vowed to defy the ruling and President Andrew Jackson took no action to enforce it.10Federal Judicial Center. Executive Enforcement of Judicial Orders
Congressional Checks
Congress holds several levers over the Court. It sets the number of justices (the Constitution does not specify nine), determines the justices’ compensation, and controls the Court’s budget and the time and place of its sessions.11Legal Information Institute. Congressional Power to Establish the Supreme Court The Exceptions Clause of Article III also gives Congress broad authority to regulate the Court’s appellate jurisdiction, which means Congress can, in theory, strip the Court of the power to hear certain categories of cases.
When Congress disagrees with the Court’s interpretation of a statute, the fix is a new law. When the disagreement is over constitutional interpretation, the only direct override is a constitutional amendment, which requires a two-thirds vote in both chambers of Congress and ratification by three-quarters of the states. That threshold is deliberately steep. Article III protects judicial independence on one specific point: a justice’s pay cannot be reduced while they remain in office, which keeps Congress from using salary cuts as a pressure tool.