Whether or not they believe they can be killed, is moot. This man cannot understand that his actions were wrong. That speaks to culpability. Any level of forethought and avoidance of repurcussions has become the determinant of constitutionality. That is too loose a definition. Simple paranoia could account for avoidance of being found out.

In this case, even your uniformed standard would not be met:

I had a six month contract back in 1996 at the FCI Beckley in WV when it was just going online for prisoner admissions after it's construction. I was an RN and was shocked at the number of inmates that were incarcerated for criminal behavior that was secondary to mental illness. We had an inmate that had to be carried from his bed every morning with his feet held up from the floor because he thought sharks were swimming on it and he'd have screaming hysterics for the rest of the day if his feet touched the cell room floor. He'd spend his time in his cell, perched on his bed, watching the sharks circle around. If he needed to use the bathroom, the CO's would have to carry him to it with small trash cans around the toilet to put his feet on so he wouldn't get bit. They usually didn't cater to prisoners like that, but it was better than listening to his banshee screams for hours if his feet touched the floor. That was just one example. The prison system is filled with the mentally ill. That's their last stop and psychiatric care is almost non-existent for them. That particular inmate hadn't seen a mental healthcare specialist in two years and didn't have any follow-up scheduled. We had inmates that barked, inmates that were autistic, inmates that were severely clinically depressed and others that had various psychosis. It was estimated back then that over a quarter of inmates that entered the system were mentally ill. I don't know if that's still the correct statistic or if our mental health system has deteriorated so badly that it's gotten worse.

the mentally ill going in and out of the criminal justice system. A week ago, my daughter, who also suffers from a mental illness, had left an AA meeting with 3 other women attendees. They were standing outside a Denny's talking when a random guy walked up to my daughter and punched her in the face. One of the other women jumped on him, he threw her to the ground, dislocating her shoulder. A third woman wrangled with him. He pummeled her and she ended up with a concussion. The guy then sat down, lit up a cigarette and said "go ahead and call the police." The cops later told my daughter and the other women that the guy had psychiatric meds in his backpack. The locked him up for disorderly conduct and told the women that it was up to them whether or not to file assault charges. They're scared to do it because then the guy would have their names. Our mental healthcare system has gaping holes in it, most generated by lack of funding.

closed down in the 60s and 70s. Look what that approach has done for private prisons and prison guard unions.

Hell, mental hospitals could have bought their own three strikes law.

We seem to be unique in confusing the second question with the first maybe because we see the mentally ill element as a get out of jail free card. If we dealt with the mentally ill component properly, it could end up with someone being out of public circulation LONGER than if they were declared competent since they have to be "cured" before they can be released.