From United States v. Pleau, 2011 U.S. App. LEXIS 20734 (1st Cir. Oct. 13, 2011):

The All Writs Act, 28 U.S.C. § 1651(a), empowers federal courts to issue extraordinary (or "prerogative") writs where "necessary or appropriate in aid of their respective jurisdictions." Writs of mandamus instruct lower courts to take certain specified acts; writs of prohibition instruct them to refrain from doing so. See In re Perry, 859 F.2d 1043, 1044 n.1 (1st Cir. 1988); In re Pearson, 990 F.2d 653, 656 (1st Cir. 1993). As such, writs of mandamus and writs of prohibition are mirror images of each other, and "derive from the same statutory basis and incorporate the same standards." In re Justices of the Superior Court Dep't of the Mass. Trial Court (In re Mass. Trial Court), 218 F.3d 11, 15 n.3 (1st Cir. 2000). We therefore "make no distinction between them," In re Atl. Pipe Corp., 304 F.3d 135, 138 n.1 (1st Cir. 2002), and "will continue the practice of referring to them interchangeably." In re Mass. Trial Court, 218 F.3d at 15 n.3.

Like mandamus, a writ of prohibition is a "drastic remedy, to be used sparingly and only in unusual circumstances." In re Mass. Trial Court, 218 F.3d at 15 (internal quotation marks omitted). The standards for determining when it is appropriate to issue a writ of mandamus or prohibition reflect the writs' anomalous character. The First Circuit has acknowledged two subspecies of mandamus writs: supervisory and advisory.

Footnote 1. Although the cases discussing the supervisory/advisory distinction do so in the context of writs of mandamus, given that writs of prohibition are "merely the obverse" of writs of mandamus, In re Atl. Pipe Corp., 304 F.3d at 138 n.1, we presume that the supervisory/advisory distinction applies in the context of writs of prohibition as well. See, e.g., In re Sony BMG Music Entm't, 564 F.3d 1, 9-10 (1st Cir. 2009) (exercising our "advisory mandamus authority" to issue a writ "prohibit[ing] enforcement of the challenged order")(emphasis added).

Supervisory mandamus is used "to correct an established trial court practice that significantly distorts proper procedure." United States v. Horn, 29 F.3d 754, 769 n.19 (1st Cir. 1994). This form of mandamus "is ordinarily appropriate in those rare cases in which the issuance (or nonissuance) of an order presents a question anent the limits of judicial power, poses some special risk of irreparable harm to the appellant, and is palpably erroneous." Id. at 769. Supervisory mandamus requires the petitioner to "show both that there is a clear entitlement to the relief requested, and that irreparable harm will likely occur if the writ is withheld." In re Cargill, Inc., 66 F.3d 1256, 1260 (1st Cir. 1995).

By contrast, advisory mandamus is not directed at "established" practices, Horn, 29 F.3d at 769 n.19, but rather at resolving issues that are "novel, of great public importance, and likely to recur." Id. at 769. A case may be fit for advisory mandamus when it presents a "systematically important issue as to which this court has not yet spoken." In re Atl. Pipe Corp., 304 F.3d at 140; see also In re Mass. Trial Court, 218 F.3d at 15 n.4; In re The Justices of the Supreme Court of P.R., 695 F.2d 17, 25 (1st Cir. 1982) (recognizing advisory mandamus as appropriate when "[t]he issue presented is novel in this circuit, it is important, and . . . may well recur before further appellate review is possible"). Advisory mandamus has its roots in the Supreme Court's acknowledgment that federal courts of appeal have "the power to review . . . basic, undecided question[s]." Schlagenhauf v. Holder, 379 U.S. 104, 110 (1964); see also Note, Supervisory and Advisory Mandamus Under the All Writs Act, 86 Harv. L. Rev. 595, 596 (1972) (describing Schlagenhauf as holding that "in certain prescribed circumstances, the courts of appeals could properly decide 'novel and important' questions of law brought to them on petitions for mandamus").***

The United States insists that Pleau's arguments do not meet the standards for mandamus. The United States argues that Pleau cannot establish (a) that he is "clearly entitled" to relief, or (b) that he is likely to suffer irreparable harm. In mounting this argument, the United States evidently presupposes that the applicable writ is supervisory in character. However, as noted above, supervisory mandamus is directed at correcting "established" trial court practices. Horn, 29 F.3d at 769 n.19. The parties, as well as the district court, have represented that Governor Chafee's denial of the United States' IAD request for custody over Pleau -- which precipitated the current appeal -- is the first time that a state has denied an IAD request by the federal government. The issue presented by this petition thus does not concern an established trial court practice, but is rather novel and a matter of first impression. It is thus more properly viewed under the rubric of advisory, rather than supervisory, prerogative writs.