his sentence in limited circumstances, including when the sentence “was imposed in violation of law.” 18 U.S.C. § 3742(a)(1). See also United States v. DeBuse, 289 F.3d 1072, 1075 (8th Cir.2002) (noting that the defendant did not assert a violation of federal statutory or constitutional law in holding that the court lacked jurisdiction to review the extent of the district court’s downward departure). Although the statute authorizes McFarlane to appeal, and we have jurisdiction, only if his sentence was in fact imposed in violation of law, we cannot make that determination without reaching the merits of his argument. We therefore must necessarily exercise “jurisdiction to determine [our] own jurisdiction.” United States v. Ruiz, — U.S. -, 122 S.Ct. 2450, 2454, 153 L.Ed.2d 586 (2002) (<HOLDING>). Pursuant to his Cooperation Agreement with
holding that a circuit court has no jurisdiction to review a district courts discretionary decision not to depart downward from the guidelines but would have jurisdiction if the district court based its decision on the belief that it did not have the authority to depart holding that the ninth circuit properly exercised jurisdiction to address defendants constitutional challenge to the district courts declination to depart downward although the challenge was ultimately denied holding that district court may not depart downward to preserve defendants ability to make restitution recognizing that a defendant may appeal a district courts refusal to depart downward if the sentence was imposed in violation of law because the district court misconstrued its authority to depart holding there was no jurisdiction to review district courts discretionary refusal to depart downward on the grounds that defendants conduct constituted a single act of aberrant behavior