What is the minimum number of justices required to agree to review a case in the Supreme Court?

The minimum number of justices required to agree to review a case in the Supreme Court is four. This process is known as the "rule of four." It allows a minority of justices to grant writs of certiorari, which enables cases to be heard by the Court. This rule serves to ensure that even if a case does not have majority support among the justices, it can still be heard if at least four justices believe it has merit.

The idea behind the rule of four is to protect minority interests within the Court and to provide an avenue for cases that may involve significant legal questions or those that could resolve conflicts in the lower court rulings. This mechanism is important for the judicial system as it allows for a broader range of issues to be considered, beyond just those that a majority of justices may find pressing. Other choices of a higher number, such as five, six, or three, do not represent the standard practice for case reviews in the Supreme Court.