Peter Hendrickson is a convicted felon and long-time promoter of a variety of tax protestor schemes. In his book Cracking the Code he claims to “prove” that the income tax only applies to people who are employed by foreign corporations or the federal government, and provides a step-by-step method for falsifying amended tax returns to get post-hoc tax rebates from previous years of income tax payment. He also runs the website Lost Horizons where people who have fallen for his scam discuss how to avoid paying taxes and how to avoid jail time and fines after the IRS has caught them avoiding paying taxes. The courts have not been very sympathetic to Hendrickson’s arguments, nor the arguments promoted by the people posting on his forums.
He is also a convicted domestic terrorist. In 1990 Hendrickson and his gang conspired to place a fire bomb in the mail, plannet to coincide with the due date for yearly income tax returns. The bomb exploded and injured a postal worker as well as a bystander. Hendrickson did get off relatively easy for that one due to his willingness to give up his fellow conspirators. In 2008, however, he was indicted on 10 counts of filing false documents with the IRS.
Diagnosis: Few people can be said to be responsible for more total time spent in prison than Hendrickson. He is, of course, stark raving mad, and so are everyone who listens to him, but his long-lasting impact is presumably limited (although his ideas will probably be reinvented again and again).