specially concurring:
Although I agree that Defendant’s conviction must be reversed, I reach that conclusion on a narrower ground.
The district court’s error was in failing to apply Federal Rule of Evidence 404(b) at all. As the majority recognizes, the court confusingly mentioned Rule 404(b) in passing but failed to analyze Defendant’s proposed evidence under that rule, including its incorporated requirement for Rule 403 balancing.1 Had the district court done so, it might have found the evidence admissible. And, had the court found the evidence admissible, the outcome of the trial might have been affected for the reasons explained by the majority.
However, in my view it is premature, and potentially unjustified, to decide that the evidence would have been admissible for sure after a full Rule 404(b) and Rule 403 analysis. Typically, when we conclude that a district court used an incorrect Rule 404(b)/Rule 403 analysis, or none at all, we remand for the district court to consider the matter in the first instance using the correct analysis. See, e.g., Blind-Doan v. Sanders, 291 F.3d 1079, 1083 (9th Cir.2002) (when a district court excluded evidence under Rules 404(b) and 415 but did not undertake the full analysis required, reversing and remanding with the caveat that, “[i]n the first instance, the balancing must be undertaken by the trial court”); United States v. Mayans, 17 F.3d 1174, 1183-84 (9th Cir.1994) (when a district court admitted evidence under Rule 404(b) but its analysis was infirm, declining to “decide whether, if the trial court had made the requisite inquiries under Rules 404(b) and 403, the prior acts evidence might still have been admissible” and leaving “the 404(b)/403 question for the district court to decide in the first instance on retrial”).
*959Additionally, in a new trial the prosecutor may not rely on the same theory. Under a different theory the evidence in question may be quite irrelevant.
Accordingly, I concur in the judgment but not in the reasoning of the majority.
. I do not agree with the majority at 956, that the district court’s implicit Rule 403 balancing under Rule 609 demonstrates an implicit Rule 403 balancing under Rule 404(b); the nature of the evidence involved, and therefore the nature of the balancing to be done, is different.