Under Welfare and Institutions Code section 709, a minor is presumed competent to undergo wardship proceedings; the burden of proof of incompetence is on the party asserting it. The minor was arrested for creating a disturbance and threatening his family with a knife. Family members told police that the minor had a history of psychological problems. A Welfare and Institutions Code section 602 petition was filed alleging the minor brandished a weapon and committed vandalism. Three weeks later defense counsel expressed a doubt regarding the minor’s competence and a doctor was appointed to evaluate the minor (Welf. & Inst. Code, § 709, subd. (a)). The doctor reported and later testified that the minor was not competent to stand trial. The court found that under section 709, a minor is presumed competent and must prove incompetency by a preponderance of the evidence. It also found the minor had not refuted the presumption of competence. The minor thereafter entered a slow plea and the petition allegations were sustained. The Court of Appeal affirmed. The California Supreme Court granted review. Held: Reversed. The constitutional right to due process of law prohibits the trial of an incompetent defendant. The proceedings by which questions regarding a minor’s competency are determined are governed by section 709. Unlike Penal Code section 1369, subdivision (f), section 709 does not expressly provide for a presumption of competence, but one is implied. This conclusion is supported by the legislative history of section 709, which reflects no intent to “alter the existing practice of presuming a minor competent to undergo a wardship proceeding and imposing on the party claiming otherwise the burden of proving incompetence by a preponderance of the evidence.” Here, the minor met this burden. The trial court unreasonably rejected the expert’s finding the minor was not competent and should have considered “appointing a second expert to inform the court’s view that the first expert’s opinion [was] inadequate.”

The standard by which an appellate court should review the trial court’s finding of competence is the deferential substantial evidence test. The juvenile court often makes its competency determination after conducting an evidentiary hearing and observing the witnesses as well the minor’s behavior and interaction with counsel. Thus, the deferential standard of review that is applied to an adult defendant’s challenge to a court’s competency determination also applies to a minor’s claim the trial court erred in finding him competent in a section 709 proceeding. Here, the evidence consisted of the opinion of a qualified expert who concluded the minor was incompetent to proceed. Based on the weight and character of the evidence, the court could not reasonably have rejected the expert’s “compelling, well-supported, and unequivocal opinion that minor was not competent to proceed to trial.”