Well, if I have a gun drawn and aimed at your head, you certainly can't win any fight with me, either. The problem lies not in the fact that you have a device which prevents me from winning any fight with you, but in the fact that the device also threatens everyone within range. A bomb is not a shield.
Assuming that the mugger was using a nuclear hand grenade, yes. But he's not. He's using a firearm. Use proportional force, ie another firearm. You're not just carrying a big gun. You're pointing that gun at everyone in range, and saying, "Better not fuck with me, or I'll blow you all away!"
It's public property. That's where the problem lies. It's his land too. Get your friends out of his shooting range, if you feel they're being threatened.
Again, a loaded gun is fine, as long as it's not being pointed randomly at people. A nuclear device is fine, as long as it's not armed. Armed is not loaded. Armed is hammer cocked and pointed.
A tool is a tool. A nuclear bomb is a tool to make a very large explosion. That explosion can be used for good (say, asteroid mining) or evil (blowing up a city). Guess which category your retributive vest falls under.
1) Assuming you get your gun out. I've taken out the uncertainty. You
will lose a fight with me. We both will. You can never win. A threat is not harm. Where's the harm? Threat is also highly subjective.
2) Why proportional force? Where's the rule saying that? You you wish to give the robber a possibility of success? Read Sun-Tsu, he's not a proponent of proportional force either. Yes, there's a risk of collateral damage. Not my problem.
3) We're back to intended use then. Something you were a proponent of earlier iirc. And for the question you ignored. My family IS leaving, it's just that they're not out yet. And he's going to shoot NOW. So, what are my options? He will not listen to my plea.
4) Where's the harm? And that's your opinion. I don't see it like that. Who's correct? Who gets to decide?
5) Thanks Cpt Obvious. I think we all know what a nuke does. Everyone should be allowed to wield that much destructive power in case they want to take up astroid mining?