What is required for the Supreme Court to hear an appeal?

For the Supreme Court to hear an appeal, at least four justices must agree to grant a writ of certiorari, which allows the case to be reviewed. This principle is known as the "Rule of Four." It is designed to ensure that a significant minority of justices finds merit in the case, which not only reflects a deliberate consideration of the issues at hand but also helps manage the Court's docket by prioritizing cases that may have broader implications.

While various other procedural and substantive requirements are necessary for a case to reach the Supreme Court, such as how lower courts handle cases and the legal questions involved, the specific need for four justices to agree is a distinctive aspect of the Court's operations. This agreement signifies a commitment to hear the case, regardless of the total number of justices available or the nature of the issues raised.