Legal Question in Criminal Law in California

Re: Mental Capacity

The first question is does the person have the mental capacity to meaningfully assist in their defense. That is a question that would look to their present status.

Lack of capacity to form the specific intent required to commit murder is an affirmative defense which is presented by the defense. There would be expert witness testimony as to whether or not the person had the ability to form the specific intent to commit murder. The prosecution would present its own witness to rebut the defensed testimony.