Thanks for your reply, DugwayDuke. I’m on vacation right now, and will read your primer link later when I’m home in my comfy chair.
For now I will point out that States already define murder and manslaughter differently, and treat it differently. Some don’t believe in the death penalty, and putting a murderer to death would itself be murder in those places. In other places, it is justice. This different treatment of rights in life and death situations has not dissolved our Republic so far.
Enjoy your vacation. I do believe the fact that state laws differ slightly is a red herring. The fact remains that killing an innocent is still murder in all states. Punishments may vary but it is still murder.