What is the standard of review for a claim of vindictive prosecution?

5 The standard of review for claims of vindictive prosecution is unsettled in this circuit. Guam v. Fegurgur, 800 F.2d 1470, 1472 (9th Cir.1986), cert. denied, 480 U.S. 932, 107 S.Ct. 1570, 94 L.Ed.2d 762 (1987). Abuse of discretion and clear error standards have been applied in various cases, and a de novo standard was used to settle the mixed question of law and fact in United States v. Martinez, 785 F.2d 663, 665 (9th Cir.1986). Regardless of which standard is applied, we reject the argument in this case.