Post-Booker, the first step in sentencing a defendant is to determine the
appropriate advisory Guidelines range, including traditional departures. See United
States v. Haack, 403 F.3d 997, 1002-03 (8th Cir.), cert. denied, 126 S. Ct. 276 (2005).
In this case, the district court inappropriately applied the § 3553(a) factors before
considering the Government's § 5K1.1 departure motion. We have made clear post-
Booker that Guideline departures remain an important and relevant part of
determining a defendant's advisory Guidelines range. See United States v. McDonald,
461 F.3d 948, 952 (8th Cir. 2006) ("The guidelines sentencing range remains the
'critical starting point' of our analysis."); United States v. Kiertzner, 460 F.3d 988, 989
(8th Cir. 2006) ("[P]ost- Booker, . . . it is necessary for sentencing courts to calculate
the applicable, advisory Guidelines range, including any traditional departures or
reductions, and use that range as one of the factors under § 3553(a) to determine an
overall, reasonable sentence."); United States v. Whitrock, 454 F.3d 866, 868 (8th Cir.
2006) ("[A] departure under Chapter 5, Part K is part of the determination of the
advisory Guidelines range."). The district court erred in failing to rule on the § 5K1.1
motion prior to considering the § 3553(a) factors.
Although the district court's failure to consider departures before considering
the § 3553(a) factors is subject to harmless error analysis and would generally be
harmless to the Government in this situation, see Pamperin, 456 F.3d at 824, it is not
harmless here where the Government challenges the reasonableness of the ultimate
sentence. A sentence within the advisory Guidelines range is presumptively
reasonable, and the farther a sentence varies from that range based on the other
§ 3553(a) factors, the more compelling the justification needs to be to support the
variance. See United States v. Beal, 463 F.3d 834, 836 (8th Cir. 2006). Thus, an
accurately calculated advisory Guidelines range, including any legitimate authorized
departure, is imperative to ascertaining the reasonableness of the ultimate sentence.
We agree with the Government that the 120-month sentence is not justified by the
§ 3553(a) factors relied upon by the district court, as explained in more detail below,