The Senate cloture rule (Rule XXII, par. 2) requires a super-majority vote to terminate a filibuster. The Appointments Clause of the Constitution, which provides that the President is to "nominate, and by and with the Advice and Consent of the Senate, ... appoint" judges, does not impose a super-majority requirement for Senate confirmation. Since it has the effect of requiring a super-majority vote on a nomination, because it usually requires the votes of 60 Senators to end a filibuster, it has been argued that a filibuster of a judicial nomination is unconstitutional. Entrenchment

Several factors have the effect of entrenching the filibuster. The Arguments of Supporters and Critics of Filibusters of Judicial Nominations

Citing the language of the Appointments Clause and the intent of the Framers, supporters and critics of filibusters of judicial nominations disagree about the relative roles of the President and the Senate in regard to judicial appointments, about whether the Senate has a duty to dispose of the President's judicial nominations in a timely fashion, and about whether a majority of Senators has a constitutional right to vote on a nomination. Standing and the political question doctrine would be the primary justiciability issues raised by a court challenge to the filibuster rule. The constitutionality of the filibuster of a judicial nomination turns on an assessment of whether the Senate's power to make rules governing its own proceedings is broad enough to apply the filibuster rule to nominations. The constitutionality of the filibuster might be challenged in court, but it is uncertain whether such an action would be justiciable.
The Senate cloture rule requires a super-majority vote to terminate a filibuster (i.e., extended debate). The Appointments Clause of the Constitution, which provides that the President is to "nominate, and by and with the Advice and Consent of the Senate, ... appoint" judges, does not impose a super-majority requirement for Senate confirmation. Critics of the Senate filibuster argue that a filibuster of a judicial nomination is unconstitutional in that it effectively requires a super-majority vote for confirmation, although the Appointments Clause does not require such a super-majority vote.
It has been argued that the Senate's constitutional power to determine the rules of its proceedings, as well as historical practice, provide the foundation for the filibuster. The question of the constitutionality of the filibuster of a judicial nomination turns on an assessment of whether the Senate's power to make rules governing its own proceedings is broad enough to apply the filibuster rule to nominations. Several factors have the effect of entrenching the filibuster (i.e., making it possible to filibuster a proposed amendment to the rules).
Supporters and critics of the filibuster of judicial nominations disagree about the relative roles of the President and the Senate in regard to judicial appointments, about whether the Senate has a duty to dispose of the President's judicial nominations in a timely fashion, and about whether a simple majority of Senators has a constitutional right to proceed to a vote on a nomination. The constitutionality of the filibuster might be challenged in court, but it is uncertain whether such an action would be justiciable (i.e., appropriate for judicial resolution). Standing and the political question doctrine would be the primary justiciability issues raised by a court challenge to the filibuster rule.
(Note: This report was originally written by [author name scrubbed], Legislative Attorney.)