Considering "theft" is a legal issue and the ones that make laws on "theft" are our representatives and we vote for our representatives I'd say 51 is the magical number. It's called Due Process which is also in the constitution.
Sorry but the people of the United States have collectively agreed that we will have a government over the areas we call the "United States of America". We have elected to give this government some powers. One of those powers is to tax.
Your consent of the tax is given when you engage in the activity that is taxed. If you do not wish to be taxed, don't engage in an activity that is taxed.