Although the U.S. Supreme Court may receive as many as 7,000 appeals (called writs of certiorari) during a term, the Court considers only about 100 cases a year; for the remainder, the decisions of the lower court stand.
How long do oral arguments last in Supreme Court cases?
For those cases that the Court decides to consider, attorneys for both sides file briefs, which are written arguments that contain the facts and legal issues involved in the appeal. The term is misleading because a "brief" may run hundreds of pages and include sociological, historical, and scientific evidence, as well as legal arguments.
Groups or individuals who are not directly involved in the litigation but who have an interest in the outcome may submit, with permission of the Court, an amicus curiae (literally "friend of the court") brief stating their position.
All cases that reach the Supreme Court have been through a lengthy appeals process and have been heard by more than one judge from a lower court. With the attorneys' briefs, any accepted amicus curiae, and the transcripts from the previous court hearings, the nine judges that sit on the Supreme Court already have a massive amount of evidence to consider before any oral arguments are even heard.
Because the judges have so much information already, attorneys don't need to present their evidence piece by piece, so oral arguments don't carry a lot of weight in the Court's final decisions. The Court allows just 30 minutes for each side to present its case, and the attorneys' arguments may be frequently interrupted by questions from the justices.