In the
United States Supreme Court, practically all final decisions are heard and decided by all nine sitting justices (unless
recused). Whereas,
federal appeals courts in the United States sometimes grant rehearing to reconsider the decision of a panel of the court (consisting of only three judges) in which the case concerns a matter of exceptional public importance or the panel's decision appears to conflict with a prior decision of the court. In rarer instances, an appellate court will order hearing
en banc as an initial matter instead of the panel hearing it first. Cases in United States courts of appeals are typically heard by three-judge panels, randomly chosen from the sitting appeals court judges of that circuit. If a party loses before a circuit panel, it may appeal for a rehearing
en banc. A majority of the active
circuit judges must agree to hear or rehear a case
en banc. The
Federal Rules of Appellate Procedure state that
en banc proceedings are disfavored but may be ordered to maintain uniformity of decisions within the circuit or if the issue is exceptionally important (Fed. R. App. P. 35(a)). Each federal circuit has its own particular rules regarding
en banc proceedings. The circuit rules for the
Seventh Circuit provide a process where, under certain circumstances, a panel can solicit the consent of the other circuit judges to overrule a prior decision and thus avoid the need for an
en banc proceeding. Federal law provides that for courts with more than 15 judges, an
en banc hearing may consist of "such number of members of its
en banc courts as may be prescribed by rule of the court of appeals." The
Ninth Circuit, with 29 judges, uses this procedure, and its
en banc court consists of 11 judges. The Ninth Circuit can theoretically rehear an
en banc decision before the full 29-judge court; but as of 2022 this has never occurred, although judges have unsuccessfully called for it in nine cases. The
Fifth and
Sixth Circuits have 17 and 16 judges respectively, but neither has adopted a limited en banc procedure. The
FISA Court sat en banc for the first time in 2017 in a case concerning bulk data collection. Although it is uncommon and not specifically authorized by any rule or statute,
federal district courts have sometimes heard cases en banc. In a 2022 article, the law professor Maggie Gardner listed over 140 potential examples, some of which later reached the Supreme Court as
Hickman v. Taylor,
Mistretta v. United States, and
Zadvydas v. Davis. == United Kingdom ==