I've never understood how people like Kyle Wagner (I mention him only because he's too amusing to forget) conflate self-defense and the defense of others with the coercion of the state. "Defense isn't voluntary to the guy trying to kill you." Yeah, no kidding. If he wasn't trying to kill me though, this would be a moot point; no one would be trying to use force against him.

Like you said @seanobi, even a cursory exploration of that premise would reveal it's incoherent and doesn't make any sense, nor is it anything anyone has proposed except for actual pacifists.