concurring.
While I concur in the result reached by the majority substantially for the reasons set forth as an alternative ground for deci*258sion, I write separately because, without regard to whether the argument was specifically brought to the attention of the district court, the government’s claim that the district court had no power to modify the plea agreement under Rule 11(e)(1)(C) of the Federal Rules of Criminal Procedure is properly before this Court.
Although this Court generally will not entertain issues on appeal which were not raised below and which would benefit from a factual record, United States v. Bowling, 351 F.2d 236, 241 (6th Cir. 1965), cert. denied, 387 U.S. 908, 86 S.Ct. 888, 15 L.Ed.2d 973 (1966), we may, in our discretion, pass on issues not raised below: (1) when the issue is one purely of law unaffected by the factual record or for which the factual record has been developed, see Hormel v. Helvering, 312 U.S. 552, 557-59, 61 S.Ct. 719, 721-22, 85 L.Ed. 1037 (1941); (2) when the parties have fully briefed the legal issue on appeal, see Cuyler v. Sullivan, 446 U.S. 335, 342 n.6, 100 S.Ct. 1708, 1715 n.6, 64 L.Ed.2d 333 (1980); Blonder-Tongue Laboratories, Inc. v. University of Illinois Foundation, 402 U.S. 313, 320 n.6, 91 S.Ct. 1434, 1438 n.6, 28 L.Ed.2d 788 (1971); United States v. Carter, 576 F.2d 1061, 1063 n.5 (3rd Cir. 1978); or (3) when justice requires such consideration, see Singleton v. Wulff, 428 U.S. 106, 121, 96 S.Ct. 2868, 2877, 49 L.Ed.2d 826 (1976); Hormel v. Helvering, supra.
Each of the three grounds justifying the consideration on appeal of issues not raised below is present herein. Whether the district court had power under Rule 11(e) to modify a Rule 11(e)(1)(C) plea agreement is strictly an issue of law; as noted by the majority, the issue was well argued by both sides; and, substantial justice is implicated in the rules governing judicial treatment of plea agreements struck between government and defendant.
Moreover, this Court is always empowered and duty bound to consider whether its jurisdictional base or that of the court below is absent. E.g., Mitchell v. Maurer, 293 U.S. 237, 244, 55 S.Ct. 162, 165, 79 L.Ed. 338 (1934). The government claims that the court is without authority pursuant to Rule 11(e) of the Federal Rules of Criminal Procedure to modify a specific sentence to which the prosecution and defense have agreed. It is clear beyond peradventure that a valid criminal rule of procedure, promulgated by authority of 18 U.S.C. §§ 3771 and 3772, may limit the subject matter jurisdiction of the federal district courts. See, e.g., United States v. Robinson, 361 U.S. 220, 80 S.Ct. 282, 4 L.Ed.2d 259 (1960). The rule that the court will always consider claims that jurisdiction is lacking is fixed by long practice and disturbed only under narrow circumstances not present in the case at bar. See Secretary of the Navy v. Avrech, 418 U.S. 676, 94 S.Ct. 3039, 41 L.Ed.2d 1033 (1974) (insufficient argument, difficult jurisdictional problem, merits determination foreordained against that party who would also lose if jurisdiction absent). I conclude, therefore, that this Court has both jurisdiction and an affirmative obligation to determine whether the district court had authority to modify the plea agreement. See, e.g., 13 C. Wright, A. Miller & E. Cooper, Federal Practice and Procedure: Jurisdiction § 3522 at 48 & n.12 (1975) and cases collected therein.
Accordingly, though concurring in the result, I do not rest my decision on the ground that the government did not first raise in the district court its argument that jurisdiction is lacking to modify the agreed sentence.