What is the burden of proving economic coercion to the defense?

We start by acknowledging that a defendant is entitled to an instruction concerning his theory of the case if it is supported by law and has some foundation in the evidence. See United States v. Echeverry, 759 F.2d 1451, 1455 (9th Cir.1985). Also, we assume, arguendo, that the "economic coercion" instruction is "supported by law" and that it has a foundation in the evidence. Given these assumptions, we must consider whether the instructions given by the judge improperly shifted the burden of proof on economic coercion to the defense.