What is the burden of proving the underlying facts by a preponderance of the evidence in a criminal case?

With respect to only a handful of defenses has the defendant been required to prove the underlying facts by a preponderance of the evidence.⁸ Those are defenses that are collateral to the defendant's guilt or innocence. The most prominent is the defense of entrapment. (See People v. Moran (1970) 1 Cal.3d 755, 760, 83 Cal. Rptr. 411, 463 P.2d 763.) "[T]he defense of entrapment ... is not based on the defendant's innocence. The courts have created the defense as a control on illegal police conduct `out of regard for [the court's] own dignity, and in the exercise of its power and the performance of its duty to formulate and apply proper standards for judicial enforcement of the criminal law.'" (Id. at pp. 760-761, 83 Cal.Rptr. 411, 463 P.2d 763.) Such defenses are collateral to the defendant's guilt or innocence because they are collateral to any element of the crime in question. Thus, the defense of entrapment does not bear on the defendant's conduct in any way, but solely on the conduct of the police.⁹