United States v. U.S. District Court

Mandamus, pronounced "man-DAME-us," is from the Latin mandare, meaning "We enjoin" or "We command." A mandamus, or writ of mandamus, is an order from a higher court or authority to a lower court or authority, enjoining it to perform a specific act or duty.

In American constitutional history, writ of mandamus made an early and significant appearance in Marbury v. Madison (1803), the first important decision by the Supreme Court.

Generally, the decisions of a lower court made in the course of a continuing case will not be reviewed by higher courts until there is a final judgement in the case. On the federal level, appellate review of lower court decisions should be postponed until after a final judgement has been made in the lower court. A writ of mandamus offers one exception to this rule. If a party to a case is dissatisfied with some decision of the trial court, the party may appeal the decision to a higher court with a petition for a writ of mandamus before the trial proceeds. The order will be issued only in exceptional circumstances.