Can a defendant change his plea and plead guilty to assault and assault with intent to commit murder?

A more troublesome problem is presented to us by our decision in Sieling v. Eyman, 478 F.2d 211 (9th Cir. 1973). There, the defendant had been charged with multiple counts of assault and assault with intent to commit murder. Three psychiatrists, after a thorough examination of the defendant, found him insane at the time the crimes were committed, but two of the three doctors found him competent to stand trial, and the trial court concluded that the defendant was competent. Shortly before trial and approximately a month after the mental examinations, Sieling notified the court that he wished to change his plea: