An anti-government activist from Montana who spoke openly of shooting police, arresting judges and burning down a local courthouse was sentenced Thursday to six years in prison on federal firearms charges.

U.S. District Judge Susan Watters said William Krisstofer Wolf had advocated a “shocking” level of violence against law enforcement, judges and other public officials.

“The public has to be protected from you,” Watters said in handing down the sentence. Wolf also would serve three years of supervised release once he’s out of prison.

A federal jury convicted the Gallatin County man in November, after Wolf bought a sawed-off automatic shotgun for $725 from an undercover FBI agent in the parking lot of a truck stop.

An automatic shotgun is categorized as a machine gun under federal law and can be bought only with a special permit, which Wolf did not have. Shotguns with shortened barrels also are illegal.

Wolf said his extreme statements pertained to an anticipated second American Revolution, and he argued they were constitutionally protected as free speech. He maintained his innocence throughout his trial.

During a sometimes-rambling, 15-minute diatribe at the sentencing hearing, he accused the FBI of twisting his previous statements and said a paid informant for the agency had lied during testimony in the trial.

“I was entrapped and ultimately denied a fair and impartial trial amounting to a political persecution,” Wolf said.

But Watters said the 53-year-old construction worker crossed the line when he purchased the shotgun. The judge said that action revealed Wolf’s propensity toward violence was real.

“You have a right to free speech, but you don’t have a right to speak as you did and then take actions” to carry out your threats, Watters said. “I’m not using anyone else’s statements against you. I’m using your own statements.”

Montana U.S. Attorney Mike Cotter said Thursday’s sentence sent a strong message of deterrence to those who espouse anarchy and seek to wage violence against the government and civil society.

Prosecutors had sought 10 years in prison for Wolf, who ran an anti-government webcast called “The Montana Republic.”

Assistant U.S. Attorney Bryan Whittaker argued that Wolf’s lack of a criminal record masked the fact that he was “building up to something big” and intended to use the shotgun to kill police.

Wolf’s attorney, Mark Werner with the Federal Defenders Office, argued that his client has no history of violence and did not intend to use the shotgun on any particular person.

“Twenty-five months of (FBI) surveillance and who did Wolf specifically threaten?” Werner said. “It’s free speech. It’s talk.”

Wolf testified at trial that he also wanted to acquire a flamethrower, which is allowed under federal law. On his webcast, Wolf compared shooting police officers to shooting gophers and proposed citizen arrests of judges by militia-like safety committees.

“Once the war starts, yes,” Wolf testified. “Not before that.”