Legal Definitions - rule of four

Rule of Four

The Rule of Four is a long-standing convention within the U.S. Supreme Court that governs its decision-making process for selecting which cases to review. For the Supreme Court to agree to hear an appeal from a lower court – a process formally known as granting a "writ of certiorari" – at least four of the nine justices must vote in favor of reviewing the case.

This rule is significant because it allows a minority of the Court to bring cases onto the Court's docket, ensuring that important legal questions or perceived errors in lower court decisions can be considered, even if a majority of the justices might initially prefer not to hear them.

Here are some examples illustrating the Rule of Four:

• Example 1: A Divided Court on a Controversial Issue

  Imagine a highly publicized case involving a new state law regulating social media content. The law is challenged in federal court, and after appeals, it reaches the Supreme Court. When the justices meet to decide which petitions for certiorari to grant, five justices vote against hearing the case, believing it's too early for the Court to intervene or that the lower court's decision was correct. However, four justices believe the case presents a crucial First Amendment question that the Court must address. Due to the Rule of Four, even though a majority (five justices) initially voted against review, the four dissenting justices' votes are sufficient to grant certiorari, meaning the Supreme Court will hear arguments and issue a decision on the merits of the social media law.

• Example 2: Ensuring Review of a Potentially Incorrect Lower Court Ruling

  Consider a complex business dispute where a federal appeals court issues a ruling that four Supreme Court justices believe fundamentally misinterprets a key federal statute, potentially creating widespread confusion for businesses nationwide. The other five justices, while acknowledging the complexity, might not see the lower court's decision as a critical error requiring immediate Supreme Court intervention. Despite this majority sentiment, the four justices' votes under the Rule of Four compel the Court to grant certiorari. This allows the Supreme Court to review the case, clarify the statute's meaning, and potentially overturn the lower court's interpretation, thereby providing legal certainty.

• Example 3: Addressing Emerging Legal Questions

  Suppose a novel legal question arises concerning the rights of artificial intelligence entities, and a lower court makes a ruling that creates significant public and legal debate. There isn't a direct conflict among different federal appeals courts (which often prompts Supreme Court review), but four justices recognize the profound societal implications and the need for the Supreme Court to provide guidance on this nascent area of law. The remaining five justices might prefer to let the issue develop further in lower courts before the Supreme Court weighs in. Nevertheless, the Rule of Four allows those four justices to vote to grant certiorari, ensuring the Supreme Court takes up this important, evolving legal question and sets a precedent for future cases involving AI rights.