Guidelines range may not be necessary”) abrogated on other grounds by United States v. Lake, 419 F.3d 111, 113 (2d Cir.2005). Rather, "to comply with Booker’s mandate that district courts 'take [the Guidelines] into account when sentencing,’ courts normally must determine and consider the correct Guidelines range.” United States v. Menyweather, 431 F.3d 692, 696 (9th Cir.2005) (alteration in original) (quoting Booker, 125 S.Ct. at 767). We leave open the question whether, and under what circumstances, district courts may find it unnecessary to calculate the applicable Guidelines range. 4 . As noted above, such application errors are still subject to harmless and plain error review. See Booker, 125 S.Ct. at 769; Williams, 503 U.S. at 202-03, 112 S.Ct. 1112; Menyweather, slip op. at 16495(<HOLDING>); Mashek, 406 F.3d at 1017; Hazelwood, 398 F.3d
holding that sentencing under the mandatory guidelines regime creates a presumption of prejudice that the government must rebut with clear and specific evidence that the district court would not have  sentenced the defendant to a lower sentence if it had treated the guidelines as advisory holding any possible error in a guidelines calculation harmless where this court was confident  that the district court could  and would  impose the same sentence again under the nowadvisory guidelines regime holding that where a district court clearly indicates that an alternative sentence would be identical to the sentence imposed under the guidelines any error that may attach to a defendants sentence under booker is harmless recognizing that any error would be harmless to the government in this case because the district court couldand wouldimpose the same sentence again under the nowadvisory guidelines regime holding that any error was harmless because under the unusual circumstances present in this thirdtime appeal we recognize that the district court could  and would  impose the same sentence again