MANDAMUS (Lat., we command). A writ or command of a court of competent jurisdiction in the name of the State, directed to an inferior court, an officer, corporation, or individual, re quiring it or him to perform a public duty as re quired by law. Historically the writ of manda 711US was at first a command of the sovereign and was without judicial character, hence it is that a mandamus is called a prerogative writ. As a purely prerogative writ its issuance was wholly a matter of discretion with the sovereign, and with its assumption of the judicial character the writ remains to some extent prerogative in the sense that it is granted at the discretion of the court. By discretion, however, is meant sound legal discretion; and the writ is now regarded as a remedy to be granted in a proper case accord ing to well-settled legal principles. The writ is a purely legal and not an equitable remedy, al though, in commanding things to be done, the court acts in personam, an exception to the usual practice of courts of law. See EQUITY.
It will be issued only when the petitioner is without adequate remedy at law, and then only to compel the performance of an official public duty which the officer, after demand, has refused or failed to perform. The duty must also he clear and undoubted, and it must be purely ministerial and not judicial or discretionary in character, for the court will not substitute for its discretion that of the officer.
The procedure upon the application for the writ and its issuance is now almost wholly regulated by statute. Consult: Spelling, Treatise on Extra ordinary Relief in Equity and Law (2d ed.. Boston, 1901) ; Wood, Treatise on the Legal Remedies of Handamus and Prohibition (3d ed., Albany, 1893).