What is the current state of the law on the doctrine of "substantial evidence" in a sexual assault case?

"`[A] defendant has a constitutional right to have the jury determine

[108 Cal.Rptr.2d 355]

every material issue presented by the evidence....' [Citations.]" (People v. Lewis (2001) 25 Cal.4th 610, 645, 106 Cal.Rptr.2d 629, 22 P.3d 392.) "To protect this right and the broader interest of safeguarding the jury's function of ascertaining the truth, a trial court must instruct on lesser included offenses, even in the absence of a request, whenever there is substantial evidence raising a question as to whether all of the elements of the charged offense are present." (Ibid.) Conversely, even on request, a trial judge has no duty to instruct on any lesser offense unless there is substantial evidence to support such instruction. (See People v. Avena, supra, 13 Cal.4th 394, 414, 53 Cal.Rptr.2d 301, 916 P.2d 1000.) "`Substantial evidence is evidence sufficient to "deserve consideration by the jury," that is, evidence that a reasonable jury could find persuasive.' [Citation.]" (People v. Lewis, supra, 25 Cal.4th at p. 645, 106 Cal. Rptr.2d 629, 22 P.3d 392.)

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