[OldMarksman]

A lawyer once told me that, in TN, deadly force may be used if "a reasonable person" perceives another person has an "intent to do harm" to one.

Careful. You may have forgotten some key parts of what he or she actually told you.

Here's what the law actually says:

A person who is not engaged in unlawful activity and is in a place where such person has a right to be has no duty to retreat before threatening or using force intended or likely to cause death or serious bodily injury if: (A) The person has a reasonable belief that there is an imminent danger of death or serious bodily injury; (B) The danger creating the belief of imminent death or serious bodily injury is real, or honestly believed to be real at the time; and (C) The belief of danger is founded upon reasonable grounds.

Emphasis added.

"Intent" isn't sufficient, the "harm" must be very severe indeed, and there must be a supportable basis for what the person "perceives.".

If a homeowner wakes up to find a stranger in their dwelling, TN assumes that the person is there to do harm just because they're there.

Here's the relevant wording:

Any person using force intended or likely to cause death or serious bodily injury within a residence, dwelling or vehicle is presumed to have held a reasonable belief of imminent death or serious bodily injury to self, family, a member of the household or a person visiting as an invited guest when that force is used against another person, who unlawfully and forcibly enters or has unlawfully and forcibly entered the residence, dwelling or vehicle, and the person using defensive force knew or had reason to believe that an unlawful and forcible entry occurred.

Do not take this as legal advice--but I have copied the law.