Imagine that your life is a video game, and the enemy you're trying to defeat is the government. The government throws lots of obstacles at you, like restrictive taxes and laws. Most people must deal with these obstacles as part of getting through the game and avoiding penalties.
But not you. You can skip right over these obstacles because you know the cheat codes — special maneuvers and magic words that not only get you out of paying for your taxes, but also keep you out of jail and maybe even get you a windfall of cash the government's been hiding from you since you were born. All you have to do is sign your name a certain way, say the right words in court and file certain paperwork, and you'll win the game and live your life free and wealthy.
This scenario approximates the worldview of sovereign citizens. Members of the sovereign citizen movement believe that anyone can avoid various unpleasant aspects of life by using special legal loopholes. They use these loopholes to attempt to dodge taxes and avoid jail time, even when they've broken the law. The Southern Poverty Law Center describes sovereign citizens as a "strange subculture ... whose adherents hold truly bizarre, complex antigovernment beliefs. Sovereigns believe that they get to decide which laws to obey and which to ignore, and they don't think they should have to pay taxes."
A closer look at the sovereign citizen movement reveals some of its byzantine legal tricks, ties to other anti-government organizations and flawed reasoning.