When the justices return to meet in conference next week and take the bench on Oct. 5, the first day of the 2026-27 term, a major focus will be on what new cases the court will add to its docket for oral argument and decision.
At the center of deciding what cases to decide is a 100-year-old custom known as the rule of four.
Simply put, this rule means that the court will hear a case when four justices vote in favor, even if a majority of justices did not want to do so. This sounds straightforward, but it comes with an interesting history and quite a few wrinkles.
Some background may be helpful. As most SCOTUSblog readers are likely aware, when the losing party in a lower court takes a case to the Supreme Court, the vehicle is called a petition for certiorari, which in Latin means “to be more fully informed.” In most of the 19th century, the path to the high court was a direct appeal, and the justices had to decide most cases that came their way.
Then in 1891, in part to ease Supreme Court backlog, Congress established the federal circuit courts of appeal throughout the country and gave the Supreme Court discretion to turn down some types of appeals from the new circuit courts. In 1925, Congress passed another law that made petitions for certiorari the predominant way to appeal to the court and gave the justices a high degree of discretion to turn away cases by simply denying review.
As part of the negotiations in 1925, justices told Congress that they generally followed the practice of agreeing to hear and decide cases if there were four justices who wanted to do so. Chief Justice William Howard Taft went farther and committed the court to the rule of four.
This “rule” is not in the Constitution, nor part of any federal law, and it does not even appear in the court’s own published rules. In 1983, Justice John Paul Stevens actually wrote a law review article questioning the rule of four, arguing that the court was taking unnecessary cases when five justices were opposed to hearing them. No change resulted from the criticism by Stevens.
The rule of four has a kind of populist appeal – that the court does not function entirely on majority rule, that a minority may push the court to decide a case, and that this may make the court more accessible to the less privileged in society. All of these ideas undoubtedly contribute to the longevity of the rule.
Understanding this practice is also important in appreciating how the court works. Each term, the court receives briefs and hears arguments in about 55-60 petitions (this number has decreased dramatically over the years). At the same time, the justices turn down some 4,000 petitions, presumably none of which received the requisite four votes. It is also worth noting that the votes of justices on granting or denying petitions and emergency applications are not necessarily publicly recorded. We learn about these practices when the papers of justices are made available, usually some years after they die.
This has led to various questions about the rule and how it works arising periodically.
One issue arises because of the dichotomy between granting certiorari and issuing emergency orders. As to the latter, it takes five votes for the court to grant a stay halting a lower court’s ruling while a case proceeds through the court system. It is possible, therefore, for the court to agree to hear and decide a petition with four votes while refusing to halt the action that is the basis for the lawsuit because there were not five votes for a stay.
This possibility was most egregious when it happened in a death penalty case. An inmate sentenced to be executed might raise an issue important enough for four justices to agree to hear the case. Meanwhile, the same inmate might be executed because there were not five votes to grant an emergency stay of execution. James Edward Smith, an inmate on death row in Texas, was executed by lethal injection on June 26, 1990. Justices William Brennan, Thurgood Marshall, Harry Blackmun, and Stevens voted to grant his petition for certiorari to consider his mental competence; because there was no fifth vote to grant a stay of execution, he was put to death which in turn made the petition moot.
This is not supposed to happen. To prevent such a situation, the court has an informal practice called the courtesy fifth vote in which a justice who opposes granting certiorari nevertheless votes to grant a stay to preserve the grant of certiorari by four justices. Two examples of this practice stood out in 2016, one in which Chief Justice John Roberts provided a fifth vote for a stay of execution, the other in which Justice Stephen Breyer was the fifth vote to delay a lower court order in favor of a transgender student. Like the rule of four, the courtesy fifth vote is purely a matter of custom and depends entirely on the good will and collegiality of the justices.
There are other questions about the rule of four that depend on court courtesy. When the court agrees to hear a case, there are important procedural issues that generally must be satisfied, such as that the case is not moot, it represents a final judgment if it is from a state court and is not purely a matter of state law, and it involves parties who have sustained a genuine injury. When one or more of these procedural hurdles exists, the court may decide to “dismiss as improvidently granted,” known as a DIG.
What happens if four justices vote to hear a case but the other five think there is a procedural flaw that justifies a DIG? To allow the five who did not want the case in the first place to simply dismiss the case would defeat the rule of four. The court’s answer appears to be another informal practice not written or codified: to dismiss a case granted by votes of four justices, it should take six votes, including one of those who voted to hear the case.
The process of granting certiorari may involve other considerations, as well. There has long been a practice called the “defensive denial.” A justice may think an issue is important and worthy of decision. However, the same justice may count votes and find that the case will come out with the opposite result. In that instance a justice may vote to deny certiorari review to avoid the loss.
Another practice depended entirely on collegiality among the justices. When the justices went around the conference table voting to grant or deny a petition, a justice might vote “join 3,” meaning he would make a fourth vote for certiorari if three others agreed to hear the case. That said, there are suggestions that the court no longer uses the “join 3” vote.
In the weeks and months ahead, the court is likely to grant review to as many as three dozen petitions for certiorari. Understanding this process provides greater appreciation of how the court makes these important choices – and how difficult it can be to separate customs from rules on the nation’s highest judicial body.
