||This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (April 2009)|
Senior status is a form of semi-retirement for United States federal judges, and judges in some state court systems. After federal judges have reached a certain combination of age and years of service on the federal courts, they are allowed to assume senior status. A judge must be at least 65 and have served for 15 years to qualify, with one fewer year of service required for each additional year of age. When that happens, they receive the full salary of a judge but work only part-time. Additionally, senior judges do not occupy seats; instead, their seats become vacant, and the President may appoint new full-time judges to fill their spots. Depending on how heavy a caseload they carry, senior judges remain entitled to maintain a staffed office, including a secretary and one or more law clerks.
Statutory requirements 
Senior status is defined by statutory law, specifically 28 U.S.C. § 371. To be in senior status, §371(e)(1) requires that a judge must be annually certified by the chief judge as having met at least one of the following criteria:
- Having carried, in the preceding calendar year, a caseload involving courtroom participation which is equal to or greater than the amount of similar work which an average judge in active service would perform in three months. §371(e)(1)(a).
- Having performed, in the preceding calendar year, substantial judicial duties not involving courtroom participation, but including settlement efforts, motion decisions, writing opinions in cases that have not been orally argued, and administrative duties for the court to which the justice or judge is assigned. §371(e)(1)(b).
- Having performed substantial administrative duties, either directly relating to the operation of the courts, or for a Federal or State governmental entity. §371(e)(1)(d)
In addition, §371(e)(1)(e) provides that a judge not meeting these criteria may still be certified as being in senior status by the Chief Justice anyway, provided that the judge did not meet those criteria "because of a temporary or permanent disability."
The United States code does not refer to senior status in its body text, although the title of 28 U.S.C. § 371 is "Retirement on salary; retirement in senior status."
Justices of the Supreme Court usually retire rather than taking senior status; a Justice having this status is thereafter referred to as a "retired justice." Senior judge is explicitly defined by 28 U.S.C. § 294, which also explicitly refers to the assignment of retired justices, making no mention of senior justice. When a circuit or district judge on senior status sits on an inferior court case, he or she is referred to as "Senior Judge" in the opinion, while a justice in the same position is referred to as "Justice, Retired."
The rules governing assignment of senior judges are also defined by statutory law, specifically 28 U.S.C. § 294. In essence, under normal conditions, the chief judge or judicial council of a circuit may assign a senior judge belonging to that circuit to perform any duty within the circuit that the judge is willing and able to perform. A senior district judge can be assigned to an appellate case, and a circuit judge can be assigned to preside over a trial. For courts that do not fall within a circuit, such as the United States Court of International Trade, the chief judge of that court can assign a senior judge of that court to perform any duty within the circuit that the judge is willing and able to perform.
In special cases, the Chief Justice can assign a senior judge to any court. This is referred to as an assignment by designation, and requires that a certification of necessity be issued by the appropriate supervisor of the court. For a circuit or district court, this supervisor is either the chief judge or the circuit justice of the circuit. For any other court, this supervisor is the chief judge of the court.
Retired justices can be assigned to any court (except the Supreme Court) the justice is willing to accept. Theoretically, a retired justice could also be assigned to act as Circuit Justice for a circuit, but this has never occurred.
In 1919, Congress created the senior status option for inferior court judges. Before the senior status option was created, a judge who reached the age of seventy with at least ten years of service as a federal judge was allowed to retire and receive a pension for the rest of his life; afterwards, a judge who qualified for retirement could instead assume senior status. John Wesley Warrington became the first federal judge to exercise this option on October 6, 1919. At that time, Warrington had been on the bench for ten years and six months, and was 75 years old.
In 1937, the option was extended to Supreme Court justices, although justices so electing are generally referred to as "retired" justices rather than as on senior status. A senior justice is essentially an at-large senior judge, able to be assigned to any inferior federal court by the Chief Justice, but receiving the salary of a retired justice. However, a retired justice no longer participates in the work of the Supreme Court itself.
In 1954, Congress modified entry requirements for the senior status option. Federal judges or justices could still assume senior status at seventy with ten years of service, but they could also assume senior status at 65 with fifteen years of service. In 1984, the requirements were further modified to what is often called the "Rule of 80": once a judge or justice reached age 65, any combination of years of age and years of service on the federal bench which totaled to eighty entitled the judge to assume senior status.
Senior status was not originally known as such. In 1919, when the senior status option was created, a judge who had assumed what we now call “senior status” was referred to as a "retired judge". The title of "senior judge" was instead used to refer to the active judge with the most seniority in a given court; after 1948, this notion was formalized and modified under the new title of "chief judge". In 1958, the term "senior judge" was given its current meaning of a judge who had assumed senior status.
Similar systems outside the US federal judiciary 
Retired Justices of the Supreme Court of the United Kingdom and certain other retired senior British judges may, at the request of the President of the Supreme Court, sit as "acting judges" on a "supplementary panel" of the Court, provided that they are below the age of 75 at the time of the request.
|This section requires expansion. (March 2010)|
Some authors have suggested that senior status may be unconstitutional.
- Stras, David R. and Scott, Ryan W. (2007). "Are Senior Judges Unconstitutional?". Cornell Law Review 92.
- 28 U.S.C. § 294 and 28 U.S.C. § 371 – statutory authorization and criterion for senior status.
- "About the Federal Judges Biographical Database". Official website of the Federal Judicial Center. Archived from the original on March 11, 2006. Retrieved September 12, 2005.
- "How One Mistake Leads To Another: A Research Note" (Word document, 89 kB). Political Analysis. Archived from the original on April 7, 2005. Retrieved May 25, 2005.