The point at which I would find armed action against the government acceptable is the point when all of our democratic institutions have broken down. As long as we still get to vote you will have much more sucess and a much easier time acomplishing your goals at the ballot box.
You will find it much easier to convince a majority of people to vote for your ideas than you will convincing a sufficient number to follow you to revolution.
If you can't convince enough people to vote for your ideas what makes you think you can convince enough people to fight and bloody themselves for your ideas?
What percentage of the population supporting an armed revolution do you think would be necessary for it to be successful? And if you say anything less than a majority aren't you essentially saying that a minority of the population would impose its will on the majority. Isn't that tyranny? And if you say a majority isn't it unnecessary as that is what is required at the ballot box?