The rule of four and role of custom on the Supreme Court

# The Rule of Four and Role of Custom on the Supreme Court

The Supreme Court's internal operating procedures have long relied on unwritten conventions and informal agreements among justices, with the "rule of four" serving as perhaps the most consequential custom governing which cases reach oral argument. This informal practice, never codified in statute or Court rule, has shaped the contours of American constitutional law for over a century.

The rule of four permits any four justices to force a vote on whether the full Court should grant a petition for writ of certiorari. If four justices believe a case warrants review, the petition advances regardless of the other five justices' positions. This mechanism emerged organically among the justices in the early 1900s and became the de facto standard for case selection. No formal document enshrines it. No statute mandates it. Yet it persists as an iron rule of Court practice.

The custom carries profound implications. It prevents any five justices from unilaterally blocking review of cases they oppose on the merits. It ensures that four dissenters can occasionally force their preferred constitutional questions before the full bench. It reflects a consensus that minority viewpoints deserve a hearing before the Court's docket. Breaking this norm would fundamentally alter how the Court manages its caseload and exercises agenda control.

The durability of the rule of four reveals something essential about how the Supreme Court actually functions. The institution relies far more heavily on custom and self-imposed restraint than on formal legal rules. The justices have never unanimously adopted a written charter governing their internal operations. Instead, generations of jurists have inherited and reinforced unwritten expectations about how the Court conducts business.

This dependence on custom creates both strength and vulnerability. Custom commands respect because it reflects accumulated wisdom and institutional stability. Justices typically honor these conventions without explicit enforcement mechanisms. The alternative, statutory regulation of Supreme Court procedures, would invite congressional interference in judicial independence. Custom preserves the Court's autonomy while ensuring predictable operations.

Yet custom lacks teeth. No statute punishes a justice who violates the rule of four. No enforcement body exists to police internal Court norms. Custom survives only through the voluntary compliance of sitting justices and their commitment to institutional continuity. Should a future majority of justices decide the rule of four no longer serves their interests, nothing prevents them from abandoning it.

Recent scholarship and debate have focused on whether unwritten rules remain adequate governance mechanisms in an era of heightened institutional distrust and partisan polarization. Some observers worry that eroding norms threaten the Court's legitimacy and functionality. Others argue the justices have consistently honored foundational customs even amid ideological disagreements.

The rule of four exemplifies how constitutional government extends beyond written text into the realm of practice and expectation. The Supreme Court operates through a blend of formal rules, statutory provisions, and customary understandings. These informal rules are not marginal quirks but central to how the institution functions. Understanding the Court requires examining not just its opinions but the invisible architecture that structures decision-making.