But I'm guessing neither of us are in that position! I guess we both live in lands that are currently governed. Now if we stripped these governments' powers back to the extent that we both agree and strip their funding back to the extent we both agree I know we still have not gone as far as you want but we still have one government. In this situation if a bundle of people (or one very rich person) decided they wanted to fund an army or a police force and do justice their way and for the sake of argument, at the risk of offending muslims out there, they decided the law they considered to be just was sharia law, would I trust them to respect the rights of suspects or to treat believers and non-believers with equal respect? Mmm. I think I would prefer to support the government in saying, "No you can't have your army" which of course means being prepared to prevent the army from being formed by force. So I don't know if I would go as far as saying I have a 'right via proxy to threaten' but I think I would nevertheless take that step in the given circumstance.
Please note I am not saying I have 'THE ANSWER' but i think I have AN answer that is a world away and is more just by orders of magnitude than what exists today. I suspect by the time we got to having stripped away the powers and funding to the extent that we both would agree the differences in the connotations and likely outcomes of the remaining options would become clearer and I doubt very much we would come to blows over it!