end of the range that the prosecutor recommended as an appropriate sentence.
II.
Castro-Juarez’s sole argument on appeal is that 48 months is an unreasonable sentence. In Booker the Supreme Court explained that sentencing judges must be guided by the factors in 18 U.S.C. § 3553(a), including the applicable guideline range, id. § 3553(a)(4); our task is to review the resulting sentence for “unreasonableness” in light of those same factors. Booker, 125 S.Ct. at 765-66; see United States v. Alburay, 415 F.3d 782, 786 (7th Cir.2005); United States v. Askew, 403 F.3d 496, 509 (7th Cir.2005). After Booker we have said that a sentence within a properly calculated guideline range “is entitled to a rebuttable presumption of reasonableness,” United States v. Mykytiuk, 415 F.3d 606, 608 (7th Cir.2005). “[T]he farther the judge’s sentence departs from the guidelines sentence (in either direction — that of greater severity, or that of greater lenity), the more compelling the justification based on factors in section 3553(a) that the judge must offer in order to enable the court of appeals to assess the reasonableness of the sentence imposed.” United States v. Dean, 414 F.3d 725, 729 (7th Cir.2005). Justifying a sentence outside the range does not require canvassing the statutory factors: “ ‘Judges need not rehearse on the record all of the considerations that 18 U.S.C. § 3553(a) lists; it is enough to calculate the range accurately and explain why (if the sentence lies outside it) this defendant deserves more or less.’ ” Id. (quoting United States v. George, 403 F.3d 470, 472-73 (7th Cir.2005)). Therefore, we are not asked to decide here whether 48 months could be a reasonable sentence; our function is to assess whether the district court’s choice of sentence is adequately explained given the record before us. Here we must determine whether the court’s articulated reasons for jumping from 21 to 48 months are sufficiently compelling on this record to satisfy us that the term imposed is reasonable.
As an initial matter, the government argues that we should not even reach this question because after the 48-month term was announced Castro-Juarez did not explicitly object to the sentence as “unreasonable.” In the government’s view, we should review Castro-Juarez’s sentence only for “plain error” rather than for reasonableness.
The government’s position has some support. In the context of supervised release revocations, where review of a prison term imposed upon revocation has always been for reasonableness, this court has held that failing to object in the district court explicitly on reasonableness grounds forfeits the argument for appeal. See United States v. Harvey, 232 F.3d 585, 587 (7th Cir.2000); United States v. Marvin, 135 F.3d 1129, 1135 (7th Cir.1998). Our decisions after Booker, however, have imposed no similar requirement and, indeed, assume the absence of any need to object to a sentence as unreasonable after its pronouncement. In appeals involving defendants who were sentenced before Booker without anticipating the decision or even recognizing the constitutional issues at stake, we routinely review the sentence for reasonableness notwithstanding the lack of objection. See, e.g., United States v. Stewart, 411 F.3d 825, 829 (7th Cir. 2005); United States v. Ramsey, 406 F.3d 426, 434 (7th Cir.2005); United States v. Paladino, 401 F.3d 471, 484 (7th Cir.2005).
We believe that the unstated assumption in our post -Booker decisions is sound. To insist that defendants object at sentencing to preserve appellate review for reasonableness would create a trap for unwary