The general rule in the federal courts is that you can only appeal if you have a final judgment. 28 U.S.C. § 1291. Of course, there are exceptions to this general rule. Some are set out in statute or rule. See, e.g., 28 U.S.C. § 1292; 9 U.S.C. § 16; Fed. R. Civ. P. 54(b). Others are established by case law. See Cohen v. Beneficial Loan Corp., 337 U.S. 541, 546 (1949); Under Seal v. Under Seal, 326 F.3d 479, 484 (4th Cir. 2003). In addition, certain rulings of the district court may be reviewed under a writ of mandamus, pursuant to the All Writs Act. 28 U.S.C. § 1651.
Writs of mandamus fall into two categories: supervisory or advisory. This article deals solely with advisory mandamus. (I have to save something to write about in future issues.) Advisory mandamus derives from the rationale, set out in Schlagenhauf v. Holder, 379 U.S. 104, 110 (1964), that such review should be available based “on the very novelty of an issue that apparently had not been presented previously to the court.” 16 Wright & Miller, Fed. Practice and Procedure § 3934.1 (3d ed. 2002).