A quick-reference glossary of the terms that appear most often in mandamus petitions and court opinions.

Mandamus filings are full of specialized vocabulary. This glossary collects the terms that come up most frequently across the articles on this site.

Petitioner and respondent

The person or entity filing the mandamus action is the petitioner. The government official, agency, or court being asked to act is the respondent. This differs from the "plaintiff" and "defendant" labels used in most ordinary civil lawsuits.

Alternative writ and peremptory writ

An alternative writ orders the respondent either to perform the act or to appear in court and explain why it should not have to. A peremptory writ is a final, unconditional order to perform the act, typically issued after the respondent has had a chance to respond.

Ministerial duty

A duty so clearly defined by law that the official has no discretion in how to carry it out — taken up in Ministerial Duty vs. Discretionary Duty.

Show cause order

A court order requiring the respondent to appear and explain, or "show cause," why the requested writ should not be granted.

Return

The respondent's formal written answer to a mandamus petition, addressing the facts and legal arguments raised.

Relator

In some jurisdictions, particularly for original proceedings in appellate courts, the petitioner is referred to as the "relator" — the party on whose behalf the writ is sought.

TRAC factors

A six-factor test, drawn from the case Telecommunications Research & Action Center v. FCC, that many courts use to evaluate claims of unreasonable agency delay.

Sua sponte

A Latin phrase meaning a court acts "on its own motion," without a request from either party — relevant when courts raise standing or jurisdictional issues themselves.

The vocabulary of an appellate petition

Fed. R. App. P. 21 supplies a small set of terms that appear on every mandamus docket in a federal court of appeals.

  • In re [petitioner]. The caption Rule 21 requires. The case is titled in the petitioner's own name because the proceeding is formally against no one.
  • Respondent. Every party to the proceeding in the trial court other than the petitioner, for all purposes. Not the judge.
  • Answer. The response a court of appeals orders within a fixed time when it does not deny the petition outright.
  • Appendix or record excerpts. The copies of the order, opinion or parts of the record essential to understanding the petition, which Rule 21 requires the petitioner to supply because the appellate court has no file of its own.
  • Invitation to the trial-court judge. The judge may request permission to address the petition but may not do so unless invited or ordered by the court of appeals.

The phrases that appear in denials

Denial language is formulaic, and each phrase traces to a specific decision. Recognising the source tells a reader which requirement the court thought was missing.

PhraseSourceWhat it signals
Clear and indisputableKerr v. United States District Court, 426 U.S. 394 (1976)The right asserted was arguable, and arguable is not enough
Drastic and extraordinary; reserved for really extraordinary causesEx parte Fahey, 332 U.S. 258 (1947)The court is invoking the discretionary character of the remedy
Judicial usurpation of power or clear abuse of discretionWill v. United States, 389 U.S. 90 (1967); Bankers Life & Casualty Co. v. Holland, 346 U.S. 379 (1953)Ordinary legal error below is not the standard
Not a substitute for appealRoche v. Evaporated Milk Association, 319 U.S. 21 (1943); Allied Chemical Corp. v. Daiflon, Inc., 449 U.S. 33 (1980)An adequate alternative remedy existed
Supervisory mandamusLa Buy v. Howes Leather Co., 352 U.S. 249 (1957)The writ used to correct a practice, not a single order
Advisory mandamusSchlagenhauf v. Holder, 379 U.S. 104 (1964)The writ used to settle an important question of first impression

Administrative-law terms a delay case turns on

Where the respondent is an agency, the operative vocabulary comes from the Administrative Procedure Act rather than from writ practice.

  • Agency action. Defined at 5 U.S.C. § 551(13) as the whole or a part of an agency rule, order, license, sanction, relief or the equivalent, or denial thereof, or failure to act.
  • Discrete agency action. The narrowing gloss from Norton v. Southern Utah Wilderness Alliance, 542 U.S. 55 (2004): one identifiable action the agency is legally required to take, not a program or a course of conduct.
  • Final agency action. The condition in 5 U.S.C. § 704 for review of action not made reviewable by another statute, available where no other adequate court remedy exists.
  • Unlawfully withheld or unreasonably delayed. The two grounds in 5 U.S.C. § 706(1), the first meaning a missed legal deadline and the second meaning excessive time where no deadline applies.
  • Within a reasonable time. The duty imposed by 5 U.S.C. § 555(b) to conclude a matter presented to the agency.
  • Committed to agency discretion by law. The exception in 5 U.S.C. § 701(a)(2) that removes a decision from judicial review entirely.

Key points

  • Rule 21 makes the opposing litigant, not the judge, the respondent, and the judge may address the petition only on invitation.
  • The petitioner supplies the record excerpts because the court of appeals has no file of its own in a mandamus proceeding.
  • Clear and indisputable comes from Kerr and signals that the asserted right was merely arguable.
  • Supervisory mandamus after La Buy targets a judicial practice, while advisory mandamus after Schlagenhauf settles a question of first impression.
  • Unlawfully withheld and unreasonably delayed are separate grounds in 5 U.S.C. § 706(1): one requires a missed deadline, the other does not.

Foundational authority

  • Fed. R. App. P. 21 — governs the form and procedure for petitioning a court of appeals for mandamus.
  • Kerr v. United States District Court, 426 U.S. 394 (1976) — sets the modern three-part test: clear right, clear duty, no other adequate remedy.
  • Ex parte Fahey, 332 U.S. 258 (1947) — describes the writ as a drastic remedy reserved for extraordinary causes
  • Will v. United States, 389 U.S. 90 (1967) — describes mandamus as a “drastic and extraordinary” remedy reserved for exceptional cases.
  • Bankers Life & Casualty Co. v. Holland, 346 U.S. 379 (1953) — the writ is not a substitute for appeal even where the ruling was wrong
Educational information only. This article explains general legal principles for research purposes and does not constitute legal advice. Mandamus procedure and standards vary by jurisdiction and change over time. If you have an active legal matter, consult a licensed attorney in your state or the relevant federal circuit.