concurring.
As the court recounts, the record in this case shows that the district court granted a substantial sentence reduction to Linda Salinas, based on her provision of substantial assistance in the investigation and prosecution of others, and then expressed frustration that Jesus Jimenez-Gutierrez, who provided no such assistance, was subject to a much lengthier term of imprisonment under the then-mandatory sentencing guidelines. It seems to me that there is a substantial question whether a district court may, in essence, create a “sentence disparity” by granting a reduction under the now-advisory guidelines to one defendant based on the provision of substantial assistance, and then “reasonably,” within the meaning of United States v. Booker, — U.S.-, 125 S.Ct. 738, 160 L.Ed.2d 621 (2005), vary from the advisory guidelines based solely on this “disparity” when sentencing another defendant who declined an opportunity to provide such assistance. Congress clearly thought it appropriate that defendants who provide substantial assistance should receive lower sentences than would otherwise be imposed, see 28 U.S.C. § 994(n); 18 U.S.C. § 3553(e), so it is difficult to conclude that Congress at the same time believed that such reductions in sentence would cause “unwarranted sentence disparities” that need to be avoided. See 18 U.S.C. § 3553(a)(6). But given the “mixed” record, I accept the court’s conclusion that there is a “reasonable probability” that the district court, if aware of Booker, would have preferred to reduce Jimenez-Gutierrez’s sentence on the basis of a perceived “sentence disparity.” And our precedent holds that the fourth prong of plain error analysis does not entail consideration of whether the proffered reason for a more favorable sentence would be reasonable with regard to 18 U.S.C. § 3553(a). Cf. United States v. Betterton, 417 F.3d 826, 833-36 (8th Cir.2005) (Hansen, J., concurring). Therefore, I concur in the decision to remand this case for resentencing, although the ultimate result may be imposition of the same sentence.