Although section 1651 was enacted in its present form in 1948, the statutory language of subsection (a) can be traced back to the original Judiciary Act of 1789, in contrast to the terminology in subsection (b), the origins of which are obscure. It is clear, however, that both the alternative writ and the rule nisi are granted on motions ex parte and are in the nature of show-cause orders. These writs were at one time used in place of the modern summons or process and also served as a means of framing the issues to be contested before a court of either original or appellate jurisdiction. Functionally the two writs are closely related, and the use of the word "or" in the statute suggests that Congress may have viewed them as interchangeable to some extent. Their operation is simple. Once a rule nisi is obtained, notice is served on the party against whom redress is sought to show cause why the requested relief should not be granted. At the hearing, argument proceeds as upon an ordinary motion except that it is the party showing cause, rather than the party who brought about the issuance of the writ, who is entitled to open and close. If the party who secured the rule nisi prevails, or if the other party defaults, the rule is made final, and the requested remedy is granted. Although the alternative ·writ, which originated with the ancient writ praecipe, is used in the United States mainly in connection with the writ of peremptory (final) mandamus, the two are to be contrasted. The alternative mandamus was once the prevalent initial step taken by one wishing to obtain the peremptory mandamus. It is a direction to the party against whom it is issued either to undertake some act or else to appear and show cause why the act need not be done. If sufficient cause 'is not shown at the hearing, a peremptory mandamus requiring performance will issue.
Michigan Law Review,
The All Writs Statute and the Injunctive Power of a Single Appellate Judge,
Mich. L. Rev.
Available at: https://repository.law.umich.edu/mlr/vol64/iss2/10