Michael Tennant shows that taxation is simply robbery under an assumed name:
It’s 2:00 AM. You are aroused from your slumber by the sound of someone’s pounding on your front door. You stumble to the door and open it to find three men in expensive, pin-striped suits who haul you off to a warehouse and, under the threat of "sleeping with the fishes," force you to fork over thousands of dollars to purchase food, clothing, medicine, and other necessities that they promise to donate to the less fortunate – although at that moment you wonder if anyone could possibly be less fortunate than you. The thugs then return you to your humble abode, warning you that they will return to "help" you engage in further "charity" in the future.
The next night, at about the same time, you are again awakened by knocking on the door. This time you find three men in cheap blue vests who march you off to Wal-Mart and force you to purchase food, clothing, medicine, and other items that you need. They then return you home along with your purchases and promise to return to "help" you obtain necessities in the future.
Question: Which of these acts is a crime?
The answer, of course, is that they both are criminal acts. In both cases you were forced to give up your property, which is to say, a theft occurred. That in one case the result was to provide for the poor and in the other the result was to provide for you is entirely irrelevant. You were coerced into handing over your rightful possessions against your wishes, and no amount of good intentions on the part of the coercer can alter that.
Read the rest, and for a more in-depth look at the subject, also see Frank Chodorov's classic essay Taxation is Robbery.