In English Law a writ was one of two things.
From mediaeval times onwards a claim could be brought before the court only if the circumstances which had occurred exactly matched the relief the court could give. Thus there was a writ of ejectment (for getting people off land) and a writ of certiorari for quashing official verdicts. This system was restrictive, and intentionally so. Giving the courts more powers would give the peasants more powers, which was not popular.
In more recent times (under the Rules of the Supreme Court, most recently 1981) a writ was the document with which a court case was commenced in the High Court of England and Wales (as opposed to a 'summons' in the County Court). The writ set out the names of the parties and the actions complained of together with the 'prayer' (the request for a remedy, such as damages).
Following the plain English ethos of the Woolfe reforms the Civil Procedure Rules did away with both writs and summonses and replaced them both with the 'Claim Form', which simply is the form to fill in if you want to make a claim.
Early U.S. law inherited the traditional English writ system, in the sense of a rigid set of forms of relief that the law courts were authorized to grant. In the United States federal court system, the All Writs Act (28 USC 1651) authorizes courts to "issue all writs necessary or appropriate in aid of their respective jurisdictions and agreeable to the usages and principles of law". However, the Federal Rules of Civil Procedure, which were adopted in 1938 to govern civil procedure in the United States District Courts, provide that there is only one form of action in civil cases, and explicitly abolish certain writs by name. Relief formerly available by a writ is now normally available by a civil action or a motion in a pending civil action. Nonetheless, a few writs have escaped abolition and remain in current use in the U.S. federal courts:
- The writ of habeas corpus, usually used to test the legality of a prisoner's detention, has expressly been preserved. In the United States federal courts, the writ is most often used to review the constitutionality of criminal convictions rendered by state courts.
- By statute, the Supreme Court of the United States uses the writ of certiorari to review cases from the United States Courts of Appeals or from the state courts.
- In extraordinary circumstances, the United States Courts of Appeals can use the common-law writs of mandamus and prohibition under the All Writs Act to control proceedings in the District Courts.
- Some courts have held that in rare circumstances in a federal criminal case, a United States District Court may use the common-law writ of error coram nobis under the All Writs Act to set aside a conviction when no other remedy is available.
- The United States District Courts normally follow state-court practice with respect to certain provisional remedies and procedures for enforcement of civil judgments, which may include writs of attachment and execution, among others.
The situation in the courts of the various U.S. states varies from state to state but is often similar to that in the federal courts. Some states continue to use writ procedures, such as quo warranto, that have been abolished as a procedural matter in federal courts.
In an attempt to purge Latin from the language of the law, California law has for many years used the term writ of mandate in place of writ of mandamus, and writ of review in place of writ of certiorari. Early efforts to replace writ of habeas corpus with writ of have the body never caught on.