How does the Supreme Court decide which cases to hear?

Almost all of the Court's docket is discretionary. A party who lost below files a petition for a writ of certiorari asking the Court to review the decision, and the justices grant review in a small fraction of cases, typically around one percent. The rule of four governs: four of the nine justices must vote to grant, which is fewer than a majority and allows a minority to force consideration of an issue. A denial of certiorari leaves the lower court decision standing but sets no national precedent and expresses no view on whether the decision was correct, a distinction frequently misreported.

What makes a case attractive for review is institutional rather than about injustice. The strongest factor is a circuit split, meaning federal appellate courts have reached conflicting conclusions on the same question of federal law, leaving the law different depending on geography. Other factors include the national importance of the question, whether the case presents the issue cleanly without procedural complications, and whether a lower court has departed from the Court's precedent. The Solicitor General's support carries substantial weight, and the Court sometimes asks for that office's views before deciding.

Once granted, the process runs through written briefs from the parties and amicus briefs from interested outside groups, oral argument typically limited to an hour, a private conference where the justices vote, and opinion assignment by the senior justice in the majority. Opinions can be majority, concurring, or dissenting, and a plurality opinion with no majority rationale creates precedent that is genuinely difficult to apply. Two other paths exist alongside the main docket: original jurisdiction over a narrow set of disputes such as those between states, and the emergency docket for applications seeking a stay or injunction on short timelines, which has drawn increasing attention for producing consequential outcomes with limited briefing and often unsigned opinions.