Technically no, but for the purposes of this debate, lets assume I still consent to the US constitution, in which case, yes, I consent to defense, since its an authorized power.
But that's just it, you're not consenting to the
Constitution. The Constitution is just a piece of paper. It tells us are rights aren't given to us, but that they are already ours, but this isn't true, at least in the a priori sense. It's only true because enough people believe it's it's true and are willing to take action to uphold it's ideas. Very good ideas, a fantastic framework unequaled throughout history, but it requires cooperation of those that believe in it.
It appears from my point of view (lest I be accused of putting words in your mouth) that you think that expecting your cooperation (in this case the compulsory surrendering of a portion of your income) is unjust. You describe it as "stealing", which frankly is just silly. It's silly because, first, the rules can be changed, and second, technically you aren't being forced to stay and consent to the rules. You are free to go. Now I don't expect that you will really go, since our rules and agreements are set upon the best framework in the world.
In-so-far as calling the taking of your money as "theft". I'd like to address this tired and often repeated slogan. Theft is to steal. To steal is; to take (another person's property) without permission or legal right and without intending to return it.
It would seem that stealing is really between people, but let's say that I concede that governments can steal, the next issue is "legal right". Does the government have "legal right"? It would seem that it does. Now you can go back to quoting portions of the Constitution if you wish, but remember, that the Constitution is only a piece of paper that derives it's value solely from the number of people that believe in it. it would appear that not everyone puts equal value in all the ideas within it. Keep that in mind.
Having said that, I don't like when the constitutional amendment process isn't followed, even if I agree with the outcome, but at the end of the day, even if you make the argument that the Constitution upholds your arguments regarding the "theft" of your money, you are forgetting that it is a document designed to change. The fact that the overwhelming majority of people understand the necessity of taxes demonstrates that if the issue of taxes were ever amended to the Constitution, NOTHING would change, thus you are holding on to idea because it is written, but your forgetting that it derives it's authority from the group (hint: even if it says it doesn't) At best you have an argument about the failure to follow the process, but at the end of the day, if the process were followed (and I agree that it should) nothing would change.
You need to come to terms with the idea that you live in a group and the group succeeds because there is a framework of rules and agreements. A flawed framework, but again, it's the best we have.