Rule of Four
RULE OF FOUR
Even before Congress expanded the Supreme Court's discretionary certiorari jurisdiction in 1925, the Court had adopted the practice of granting certiorari whenever four of the nine Justices agreed that a case should be heard. This "rule of four" was first made public in testimony concerning the bill that became the 1925 act. Some commentators have seen the adoption of that act as a congressional ratification of the practice; in any case, the rule is well established. In Rogers v. Missouri Pacific R.R. (1957) a majority agreed that the rule required the Court to hear a petition granted on the vote of four Justices, even though the other five might still think the case unworthy of review, unless new considerations had come to light in the meanwhile. As New York v. Uplinger (1984) makes clear, however, the vote of four Justices to hear a case does not require the Court to decide it if the other five Judges think a decision inappropriate.
The Court follows a similar practice in appeal cases coming from the state courts. The Court has even dismissed such an appeal "for want of a substantial federal question " over the expressed dissent of three Justices. When three members of the Court argue that a question is a substantial one, it probably is. The dismissal of an appeal under these circumstances reinforces the view that appeal, despite its theoretically obligatory nature as defined by Congress, has taken on much of the discretionary quality of the Court's certiorari policy.
Kenneth L. Karst
Leiman, Joan Meisel 1957 The Rule of Four. Columbia Law Review 57:975–992.