People v. Samuel

*494Opinion

MOSK, J.

It is a fundamental canon of criminal law, and a foundation of due process, that “A person cannot be tried or adjudged to punishment while such person is mentally incompetent.” (Pen. Code, § 1367; Pate v. Robinson (1966) 383 U.S. 375, 378 [15 L.Ed.2d 815, 818, 86 S.Ct. 836]; People v. Laudermilk (1967) 67 Cal.2d 272, 282 [61 Cal.Rptr. 644, 431 P.2d 228]; People v. Pennington (1967) 66 Cal.2d 508, 516-517 [58 Cal.Rptr. 374, 426 P.2d 942].) We have heretofore defined the threshold requirement of substantial evidence of mental incompetence that entitles a defendant to a hearing to…