Can a defendant be found mentally incompetent to stand trial?

^3. Section 1367, subdivision (a), states "[a] person cannot be tried or adjudged to punishment while that person is mentally incompetent. A defendant is mentally incompetent... if, as a result of mental disorder or developmental disability, the defendant is unable to understand the nature of the criminal proceedings or to assist counsel in the conduct of a defense in a rational manner."

^4. People v. Marsden (1970) 2Cal.3d 118.