In British and American common law, quo warranto (Medieval Latin for "by what warrant?") is a prerogative writ requiring the person to whom it is directed to show what authority they have for exercising some right, power, or franchise they claim to hold.
With the spread of royal justice in the 12th and 13th centuries, private franchises and liberties were increasingly called upon to uphold the king's peace: to act against "malefactors and peace breakers, so that it may appear that you are a lover of our peace". From 1218 onwards, royal Eyres also began using the old writ of quo warranto - a court order to show proof of authority, as for example (literally) "By what warrant are you the sheriff?" - to investigate the origins of such franchises. An inquest of 1255 began examining such liberties nationwide; and the same enquiry was taken up again by King Edward I of England in 1278, when he decreed in the Statute of Gloucester that "We must find out what is ours, and due to us, and others what is theirs, and due to them".
From one point of view this can be seen as an attempt to investigate and recover royal lands, rights, and franchises in England, in particular those lost during the reign of his father, King Henry III of England. From another, it was less of an attack on franchises as a clarification of them: in Hilda Johnstone's words, "Edward's aim, it is clear, was from the first not abolition but definition".
A similar ambiguity surrounds the role of the justices that, from 1278 to 1294, Edward dispatched throughout the Kingdom of England to inquire "by what warrant" English lords claimed their liberties and exercised jurisdiction, including the right to hold a court and collect its profits. Some of the justices demanded written proof in the form of charters, others accepted a plea of "immemorial tenure"; and resistance and the unrecorded nature of many grants meant that eventually, by the Statute of Quo Warranto (1290), the principle was generally accepted that those rights peacefully exercised since 1189 - the beginning of the reign of Richard I, which is the legal definition in England of the phrase "time immemorial" - were legitimate.
The most famous historical instance of quo warranto was the action taken against the Corporation of London by Charles II in 1683. The King's Bench adjudged the charter and franchises of the City of London to be forfeited to the Crown, though this judgment was reversed by the London, Quo Warranto Judgment Reversed Act 1689 shortly after the Glorious Revolution.
But the remodelling of the City of London was only part of a wider remodelling of some forty chartered parliamentary boroughs by the Crown - a policy taken up again in 1688 by James II, when some thirty-five new charters were issued after quo warranto produced the surrender of the old ones. This Quo Warranto remodelling or 'dissolution' of the parliamentary corporations gave point to the claim by William III that "our expedition is intended for no other design but to have a free and lawful parliament assembled", and underpinned the charge in the Bill of Rights that James had been "violating the freedom of election by members to serve in parliament".
In the United States today, quo warranto usually arises in a civil case as a plaintiff's claim (and thus a "cause of action" instead of a writ) that some governmental or corporate official was not validly elected to that office or is wrongfully exercising powers beyond (or ultra vires) those authorized by statute or by the corporation's charter.