What is the test for proving vindictive prosecution?

To establish that the government's actions amounted to vindictive prosecution, Scholz must demonstrate either actual vindictiveness, which requires "direct evidence of an expressed hostility or threat to [him] for having exercised a constitutional right," United States v. Gallegos-Curiel, 681 F.2d 1164, 1168 (9th Cir.1982) (citations omitted), or presumptive vindictiveness, which requires "an initial showing that charges of increased severity were filed because [he] exercised a statutory, procedural, or constitutional right in circumstances that give rise to an appearance of vindictiveness," id. (citations omitted). If Scholz succeeds in demonstrating presumptive vindictiveness, the burden shifts to the prosecution to "dispel the appearance of vindictiveness." Id. (citations omitted).