What is the current state of the law on the doctrine of an aider and abettor of a crime?

The reasoning of Ellhamer and Ott has been forcefully and correctly criticized by a number of subsequent Court of Appeal opinions which find that the weight of authority requires an aider and abettor to have an intent or purpose to commit or assist in commission of the underlying offense. The leading case is People v. Yarber, supra, 90 Cal.App.3d 895, 153 Cal.Rptr. 875, which explained that "[t]he Ellhamer/Ott synthesis that intent is inferred from the knowledge by the aider and abettor of the perpetrator's purpose is sound, generally, as a matter of human experience, but we cannot extrapolate therefrom, as a matter of law, that the inference must be drawn. Intent is what [35 Cal.3d 558] must be proved; from a person's action with knowledge of the purpose of the perpetrator of a crime, his intent to aid the perpetrator can be inferred. In the absence of evidence to the contrary, the intent may be regarded as established. But where a contrary inference is reasonable--where there is room for doubt that a person intended to aid a perpetrator--his knowledge of the perpetrator's purpose will not suffice." (Fn. omitted; original emphasis.) (90 Cal.App.3d at p. 916, 153 Cal.Rptr. 875.)