Rule of Four Law and Legal Definition

Rule of four refers to a convention that for certiorari to be granted by the U.S. Supreme Court, four justices must vote in favor of the grant. The rule ordains that the votes of four Justices are needed to grant certiorari and bring a case before the Court for decision on the merits. Certiorari is an extraordinary writ issued by an appellate court, at its discretion, directing a lower court to deliver the record in the case for review. The U.S. Supreme Court uses certiorari to review most of the cases that it decides to hear.