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The Supreme Court's Rule of Four

On the face of it, the Supreme Court’s “Rule of Four” is straightforward. Where the justices have discretion as to whether to hear an appeal, at least four of the Court’s members must vote to grant a writ of certiorari, which facilitates a full review on the merits. The rule’s history is somewhat less simple, however. It began in the early nineteenth century as an informal—perhaps even unstated—practice that applied only to a small subset of the Court’s caseload. Nevertheless, an early iteration of the Rule of Four played a significant role in Congress’s 1925 grant of broad discretion over most appeals. From that point, the rule took several decades to arrive at its present form, with both the number of justices required to ensure review and the practical effect of a vote to hear a case initially unclear. While debates over these details may seem technical at first blush, they forced the Court to reckon with important institutional considerations such as the balance between efficiency and doing justice in individual cases, the appropriate standards for case selection, and the importance of majority rule on the nation’s highest court. This spotlight examines the rule’s early history with a view toward illuminating these themes.

In the first few decades of the twentieth century, Congress granted the Supreme Court increasing control over its docket in a range of matters, including patent, admiralty, and bankruptcy suits, as well as personal injury cases arising under federal tort statutes. Laws granting the Court this discretion generally did so by making review contingent on the justices granting a writ of certiorari. Congress left it to the Court to decide when certiorari was appropriate, and the justices quickly settled on a procedure whereby each justice would indicate whether he thought the case was appropriate for review. This process appears to have been flexible as to how many justices were required to favor review, though a majority was never necessary.

The certiorari process came into sharper focus during congressional hearings over the most important legislation dealing with the Court’s appellate docket, the Judiciary Act of 1925 (commonly known as the “Judges’ Bill”). Whereas previous statutes had restricted case selection to distinct subcategories of the Court’s appellate caseload, the Judges’ Bill permitted the justices to choose whether to hear most appeals from state supreme courts and federal courts of appeals. The bill promised to ease docket congestion by allowing the Court to focus on cases of national importance. The proposed legislation had a broad base of political support, but some worried that the Court might use its case-selection powers to avoid difficult or delicate issues.

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To assuage these concerns, some of the Court’s sitting justices testified before Congress as to their existing practices for sifting certiorari petitions. The justices’ testimony in these hearings introduced the notion of an unwritten rule whereby the support of four (and sometimes fewer) justices was sufficient to ensure review. Justice Louis Brandeis, appointed in 1916, stated that he could not remember an instance in which the Court had not opted to hear a case for which at least four justices had supported granting the writ. Justice Willis Van Devanter testified that, “We always grant the petition when as many as four think that it should be granted and sometimes when as many as three think that way.” This interpretation of the rule appears to have persisted for several years after the passage of the Judges’ Bill. (Writing in 1937, Chief Justice Charles Evans Hughes observed that “if two or three of the Justices are strongly of the opinion that certiorari should be allowed, frequently the other Justices will acquiesce in their view.” But “the petition [was] always granted if four [justices] so vote.”)

The justices’ congressional testimony suggested that deference to the minority was a function of the preliminary nature of the certiorari grant. A lower bar was necessary to prompt a fuller consideration of a case than was needed to prevail on the merits. Awareness of the rule also helped ease some politicians’ concerns that important cases might escape scrutiny through an expanded certiorari process, and the Judges’ Bill passed with overwhelming support.

The Rule of Four’s role in informing Congress’s actions led some later justices to conclude that the Court would need to inform Congress of any major changes to the rule. Nevertheless, incremental developments took hold in the decades that followed the Judges’ Bill. The Court gradually adopted the view that four votes should serve as a hard minimum to ensure discretionary review, irrespective of the strength of feeling of those in the minority. The impact of this shift was arguably softened to some extent as some justices began to cast “join-three” votes by the early 1970s. These votes indicated that a justice might support a grant of certiorari provided three others agreed to do so. The four-justice standard has proven remarkably durable. Although Justice John Paul Stevens attempted to persuade his fellow justices to increase the minimum for review to five votes in the 1970s, the Court has continued with the Rule of Four to the present day.

The number of votes necessary to secure review was not the only issue raised by the Rule of Four. Justices often debated what effect the rule had on the cases that received at least four votes. Did the grant of certiorari guarantee a decision on the merits or merely that the Court would consider a case more closely? In his 1925 testimony, Justice Van Devanter had emphasized that the grant of certiorari “means, and only means, that the court finds probable cause for a full consideration of the case in ordinary course.” Further scrutiny might disclose elements of a case that rendered it inappropriate for Supreme Court review. Similarly, events occurring after the initial grant of certiorari might cause a case to become moot or otherwise unsuitable for decision on the merits. In such cases, there would be little sense in going through the motions of a hearing and formal decision. In fact, proceeding would defeat a major purpose of certiorari, namely, promoting judicial efficiency by eliminating frivolous or otherwise unsuitable matters.

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Starting in 1911, the Court had developed a procedure for dismissing cases that further review showed should not have been granted a writ of certiorari. In such circumstances, the Court would dismiss the case on the ground that certiorari had been “improvidently” granted, rather than proceed to oral argument or a decision on the merits. When the justices disagreed as to whether a grant of certiorari had been appropriate, however, the course was less clear. This was particularly so in cases where only four justices had supported certiorari, since the five remaining justices could vote to dismiss the case. In a 1952 dissenting opinion, Justice William O. Douglas argued that this feature of the Rule of Four meant that “only those who voted to grant the writ” should have the privilege to vote to dismiss the writ as improvidently granted. Were it otherwise, he reasoned, the Court would be left in a position in which the “integrity of the four vote rule would … be impaired” because the four justices who had voted to hear the case could not “get a decision of the case on the merits.” On this reasoning, the Rule of Four might dictate continued review of a case, even if the Court’s majority would have voted to dismiss.

As a corollary to this concern, the rule also set no fixed standards establishing which cases merited full consideration. In the 1940s and 1950s, debate over the kinds of appeals the Court should hear occasionally spilled over into the pages of the U.S. Reports, as several justices attempted to cast votes at the decision stage based on a belief that the Court should not have taken a case. Often, these justices suggested the appeal did not raise issues likely to affect other cases. Congress, they argued, had granted the power to deny appellate review based on a vision of the Supreme Court as an institution that would set major legal principles or resolve competing rulings from the U.S. courts of appeals. Justice Felix Frankfurter became particularly vocal about this aspect of certiorari policy during the late 1940 and 1950s. He regularly objected to the review of fact-intensive tort cases arising under statutes such as the Jones Act, the Tort Claims Act, and the Federal Employers’ Liability Act. In several of these cases, Justice Frankfurter declined to vote on the merits, instead arguing that the Court should not have granted certiorari in the first place. (An earlier spotlight discussed four such cases and the consensus view of the Court that Justice Frankfurter’s abstention was inappropriate.)

Justice Frankfurter’s actions raised questions as to how justices should respond to grants of certiorari they deemed improvident. Most of the Court’s members emphasized the concern earlier raised by Douglas that Frankfurter’s approach might endanger the Rule of Four’s viability by allowing justices who disagreed with a grant of certiorari to avoid further consideration of the matter. In McBride v. Toledo Terminal Co. (1957), Frankfurter attempted to defend his policy in terms of judicial restraint and perhaps even ethical considerations:

Abuse of judicial discretion is a technical phrase to express a misconception of the judicial function as exercised in a particular situation. There is no appeal from such abuse of judicial discretion by this Court. When there is such a misuse of power, as I deem it to be in making an exception, in effect, if not formally, of cases … that turn merely on evaluation of evidence, only the individual conscience remains.

Though Frankfurter deemed a refusal to participate in a decision on the merits the only conscientious path, later justices generally contented themselves with dissenting from a grant of certiorari or noting their rationale for believing the writ improvidently granted in an opinion on the merits, rather than declining to rule. Nevertheless, the issues Justice Frankfurter raised have continued to figure in decisions over whether a grant of certiorari is appropriate under the Rule of Four.

That such a seemingly clear-cut rule triggered so much debate in the decades following its introduction suggests how important judicial procedures not dictated by statutes or laid down in landmark decisions can be. By the same token, the Rule of Four’s durability suggests that rules created in less formal ways than these may nevertheless stand the test of time in providing useful guidance to judges and litigants.

Winston Bowman, Associate Historian
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Related FJC Resource:
Selected Developments in the History of Supreme Court Jurisdiction

Further Reading:
Leiman, Joan Maisel. “The Rule of Four.” Columbia Law Review 57, no. 7 (1957): 975–992.

O’Brien, David M. “Join-3 Votes, the Rule of Four, the Cert. Pool, and the Supreme Court’s Shrinking Plenary Docket.” Journal of Law & Policy 13, no. 4 (1997): 779–808.


This Federal Judicial Center publication was undertaken in furtherance of the Center’s statutory mission to “conduct, coordinate, and encourage programs relating to the history of the judicial branch of the United States government.” While the Center regards the content as responsible and valuable, these materials do not reflect policy or recommendations of the Board of the Federal Judicial Center.