A Bucks County software engineer who took to a federal jury his belief that paying federal taxes is voluntary was sentenced yesterday to the maximum 27 months in prison and ordered to start paying almost $83,000 in back taxes.

Arthur L. Farnsworth, 43, was taken into custody immediately on the motion of Assistant U.S. Attorney Ara B. Gershengorn, who told U.S. District Judge John R. Padova that Farnsworth had twice violated the terms of his pretrial release.

Gershengorn said Farnsworth had been stopped once driving under the influence of alcohol and had not surrendered a handgun to authorities until Monday.

Farnsworth, of Sellersville, a former Libertarian candidate for Congress and a tax protester who once operated his own Web site espousing his beliefs, was convicted of tax evasion in December.

At trial he was no less candid, telling the jury that his own research had convinced him that federal tax payments were voluntary. Farnsworth even agreed with the Internal Revenue Service's estimate of $288,000 as his gross income earned over the 1998, 1999 and 2000 tax years, when he did not file tax returns or pay taxes.

Prosecutors, however, argued that Farnsworth's research into the federal tax system was groundless, created to cover his personal political beliefs.

In addition to the prison term - the maximum recommended under federal sentencing guidelines - the judge fined Farnsworth $500 and ordered him to cooperate with IRS investigators in documenting his finances and beginning to pay his tax debt.

Farnsworth promised to cooperate.

Prosecutors said Farnsworth transferred his money to overseas bank accounts and put it into bogus trusts to try to stay ahead of the IRS.

In 2002 the IRS raided Farnsworth's Bucks County home and found documents detailing some of the trust funds. The documents resulted in a nationwide probe of fraudulent trusts that led to charges against other people, including actor Wesley Snipes.

Contact staff writer Joseph A. Slobodzian at 215-854-2985 or jslobodzian@phillynews.com.