What is mandamus?

Sheridan Green

6/25/2026

People are always asking us “What is mandamus?” This post will explore the topic.

What is a mandamus?

“Mandamus” is a writ or an action you can ask a court to take involving ordering another court or an agency to do something. “Mandamus” is from a Latin word which means “we command.”

There are two different general statutes that give jurisdiction to a federal district court for mandamus and at least one special one for a specific kind of case.

The first is the mandamus statute, 28 USC § 1361. It is very short. It is called “Action to compel an officer of the United States to perform his duty” and says, “The district courts shall have original jurisdiction of any action in the nature of mandamus to compel an officer or employee of the United States or any agency thereof to perform a duty owed to the plaintiff.”  

The other general statute that contains mandamus-like language is the Administrative Procedure Act. 5 U.S.C. § 706 says: “To the extent necessary to decision and when presented, the reviewing court shall decide all relevant questions of law, interpret constitutional and statutory provisions, and determine the meaning or applicability of the terms of an agency action. The reviewing court shall…compel agency action unlawfully withheld or unreasonably delayed.”

Most mandamus actions under the APA cite to the “unreasonably delayed” language above. But there is some really cool caselaw about “unlawfully withheld” as well.

Requirements of mandamus:

In any mandamus action you have to make the case that the applicant (1) “has a clear right to the relief requested” (2) “the defendant has a clear duty to perform the act in question;” and (3) “no other adequate remedy is available.”

One and two usually go together. In the strongest mandamus cases, a statute gives the applicant a clear right to the relief requested which also creates a duty by the government to give you that relief. Such statutes often use the magic word “shall.” But many other statutes are permissive—they give the agency discretion to grant the relief but use a softer word like “may.” Still, most courts have held that even if the statute says the agency “may” grant you relief, they at least owe you the duty to decide one way or the other instead of dragging their feet.

The third requirement is that the applicant show she doesn’t have some other option she has to try first before coming to the court.

Reasonableness of the delay

The APA specifically calls out agency action which has been “unreasonably delayed” and mandamus act cases similarly hold that a government “duty” to adjudicate an application can be created by unreasonable delay. So how do courts determine whether a delay is reasonable?

The most famous “reasonableness” case is called Telecomm. Research & Action Ctr. v. FCC, 750 F.2d 70, 80 (D.C. Cir. 1984). The case set out the following factors for a court to consider:

(1) the time agencies take to make decisions must be governed by a “rule of reason”;

(2) where Congress has provided a timetable or other indication of the speed with which it expects the agency to proceed in the enabling statute, that statutory scheme may supply content for this rule of reason;

(3) delays that might be reasonable in the sphere of economic regulation are less tolerable when human health and welfare are at stake;

(4) the court should consider the effect of expediting delayed action on agency activities of a higher or competing priority;

(5) the court should also take into account the nature and extent of the interests prejudiced by delay;

(6) the court need not find any impropriety lurking behind agency lassitude in order to hold that agency action is unreasonably delayed.

Practical considerations in filing a mandamus action

Often the strategic value of filing a mandamus action is in forcing a quick settlement with the federal government. Not always--but very often--once the suit is filed the agency will expedite the benefit request (or find whatever drawer it got stuffed into when the officer was scratching his head over a complicated issue) and you’ll see an adjudication within about 60 days. This is the optimal outcome. Like almost all litigation, a mandamus action, if pursued to a judicial resolution, is neither cheap nor fast nor certain. However, it’s not cheap or fast or certain for the government either. So, like most litigation, there is strong incentive to end the fight early on. It is very easy for the federal government to simply adjudicate the petition and then ask for the case to be dismissed.