Legal Question in Criminal Law in California

Re: parameters of a guilty verdict

In extraordinary cases the court can void or reduce a conviction which it feels is unsupported by the evidence. The reason such cases are extraordinary is that the judge is supposed to weed out such charges *before* the case goes to the jury. A judge who thought there was enough evidence to support a charge when the jury begins deliberation is unlikely to have a different opinion when the jury returns with a verdict. While courts rarely do this on their own, it is somewhat more common for the court to make such an order in response to a motion by the defendant, since a persuasive motion can lead a judge to change his mind about the sufficiency of the evidence.

And you are also correct that a judge cannot override a jury's verdict of not guilty. The right to a trial by jury means that the judge convict someone the jury has acquitted, since the resulting verdict would be contrary to the jury's findings.

In some jurisdictions there is an exception to this rule where the defendant has tampered with the jury by bribing, threatening or lobbying some of its members. Such cases are very rare, and it is even more rare for the trial judge to find out about such events before she must enter judgment.