Bit of a false dichotomy there, maybe? In Australia, as in the US, criminal defendants mostly do not take the stand. They can’t all be relying on the authority and reliability of the church.
Nor did Cardinal Pell. The thrust of his defence was not “I’m a cleric - I couldn’t possibly have done this!” It was more an attack on the coherence and credibiltity of the prosecution case, pointing to discrepancies in the evidence, aspects of the story which seemed very implausible, that kind of thing.
Obviously, I’m not privy to the discussions about whether he should take the stand or the factors that went into the decision that he should not, but there’s an obvious consideration - the guy is widely, if not quite universally, disliked by people who have had dealings with him. And a significant part of this is a poor affect that comes off as arrogant, abrasive and disdainful. His friends say that’s not who he is at all, that beneath that gruff exterior there lurks etc etc, but even if that’s true it’s not a truth likely to come across in the witness box. I suspect his performance on cross-examination could be disastrous; it would be trivially easy to make him look like a bully and, once you’ve made an accused abuser look like a bully, you’re half-way there. So the decision not to give evidence was not a surprising one.
An insanity plea requires that the person did not know right from wrong. This is a departure from an earlier standard which allowed insanity when a person, who might have know what they did was wrong, was driven by an ‘irresistible impulse’.
Neither touches on the issue you are addressing, which is whether the Defendant is competent at trial. A person who is legally insane might be competent; a person who is incompetent might not have been legally insane. The issue of competency is one of whether the person can understand the proceedings and assist in his own defense. If you, as a lawyer, were to try to talk to your client about the victim and he invariably responds with a diatribe about an old movie, you will need to consider whether to invoke a competency claim (mainly because you can’t get useful information from your client about their case).
If a person is incompetent, they can’t be tried. They won’t be released, however - instead, they’ll be locked up (and, in theory, given treatment) either until they can be restored to competency or until the time they are detained equals the possible criminal penalty the person faced at trial.
So, in your scenario, I don’t think it would be helpful for a Defendant to get on the stand and start speaking nonsense. It will almost certainly delay the trial, but it won’t allow the person to avoid a determination of guilt and it doesn’t directly go to whether, at the time of the crime, they understood what they were doing.
locally we had a guy take the stand in a murder trial. Ended with a hung jury but the 2nd trial he did not take the stand and was convicted. He wasn’t even arrested until 3 years or so after the murder of his wife. the prosecution theory was he left town for a business trip and then drove back late at night to murder his wife and then went back to his trip. One mistake he made was screaming at a clerk at a convenience store on his way back to town and she remembered him.
Years ago we had a case where the accused, son of a former Premier and himself a former Cabinet minister, was charged with the brutal murder of his ex-wife, named Joanne.
He went into the witness box and testified. The Crown, one of the best Crowns in the province, if not the country, did a very thorough cross. He also knew that the accused had a short temper, and kept asking questions that were likely to trigger that temper.
Sure enough, after one of the questions, the accused stood up in the witness box and angrily said something to the effect of “If I was able to, I would meet you outside and we’d have it out.”
Judge immediately called a 20 minute adjournment to let things cool down.
After the adjournment, Crown resumes his cross:
“Tell me, did you ever get as angry at Joanne as you did with me just before the break?”
Doesn’t matter how the accused answers. The Crown has graphically shown that the accused has a short temper and is willing to use violence against someone he’s mad at.
He relied on members of his church to say “He couldn’t have done that!”, – in a case where the reliablity and objectivity of the members of his church was itself in question. And if he had stood up and said “I’m a cleric - I coulnd’t possibly have done that”, at least he wouldn’t have got a worse result.