Is a federal district court's formulation of jury instructions for abuse of abuse of power a matter of law?

We review the district court's formulation of jury instructions for abuse of discretion. See United States v. Wellington, 754 F.2d 1457, 1463 (9th Cir.), cert. denied, 474 U.S. 1032, 106 S.Ct. 592, 593, 88 L.Ed.2d 573 (1985). See also United States v. Echeverry, 759 F.2d 1451, 1455 (9th Cir.1985) ("So long as the instructions fairly and adequately cover the issues presented, the judge's formulation of those instructions ... is a matter of discretion."). Pace is entitled to his proffered instruction only if his theory of the case is "supported by law and has some foundation in the evidence." Id.