What are the elements of section 4500 of the California Criminal Code and what is the effect of the court's order excluding evidence of a prior murder conviction at petitioner's trial?

The elements of the offense set forth in section 4500 are (1) an aggravated assault, (2) by a state prisoner, (3) Serving a life term, (4) with malice aforethought. (People v. Noah, supra, 5 Cal.3d at p. 477. 96 Cal.Rptr. 441, 487 P.2d 1009.) ² The court's order excluding evidence of the prior murder conviction at petitioner's trial for violation of section 4500 in effect precludes the People from producing evidence to establish one of the necessary elements of the offense, i.e., that real party was serving a life term. The order excluding evidence terminates the prosecution under section 4500 for all practical purposes, since to proceed with the trial without evidence of a necessary element of the offense would be an exercise in futility.