Does the Double Jeopardy Clause apply to federal prosecution?

Whether a defendant's double jeopardy rights have been violated is a question of law, which this court reviews de novo. United States v. Horodner, 993 F.2d 191, 193 (9th Cir.1993).

All three of the appellants allege that under United States v. Halper, 490 U.S. 435 (1989), the federal prosecution was barred by the Double Jeopardy Clause, because the state of Oregon had earlier obtained an injunction, damages, litigation costs and attorneys' fees against them and the dual-sovereignty doctrine does not apply.