Does the doctrine of ex post facto prohibition apply?

"[T]he ex post facto prohibition ... forbids the imposition of punishment more severe than the punishment assigned by law when the act to be punished occurred." Weaver v. Graham, 450 U.S. 24, 30 (1981). "Absent a court pronouncement on the matter, the interpretation of the relationship between the statutes placed upon them by the administrative agency charged with their enforcement has the force and effect of law." Love v. Fitzharris, 460 F.2d 382, 385 (9th Cir.1972), vacated as moot, 409 U.S. 1100 (1973).

This court has "distinguished between a change in an administrative interpretation of state law made by the agency itself, ... and a court decision authoritatively construing state law. In the latter case, we noted, the ex post facto clause by its own terms does not apply." Holguin v. Raines, 695 F.2d 372, 374 (9th Cir.1982), cert. denied, 464 U.S. 896 (1983). However, the principle of fair warning "implicit in the ex post facto prohibition requires that judicial decisions interpreting existing law must have been foreseeable." Id.