Can a defendant preclude the government from proving intent by focusing his defense on other elements of his crime?

... [The defendant] cannot preclude the government from proving intent simply by focusing his defense on other elements of his crime. [The defendant's] choice of defense did not relieve the government of its burden of proof and should not prevent the government from meeting this burden by an otherwise acceptable means. Rule 404(b) permits the government to prove intent by evidence of prior bad acts, and we have already held that admission of such a proof in this case was not an abuse of discretion under the rule.

United States v. Hadley, 918 F.2d 848, 852 (9th Cir.1990), cert. dismissed, 113 S.Ct. 486 (1992).