(CNN) — Stewart Rhodes, the founder and leader of the Oath Keepers, was sentenced to 18 years in prison on Thursday for leading a far-reaching plot to keep then-President Donald Trump in power after he lost the 2020 election.

The sentence is the first handed down in over a decade for seditious conspiracy.

“What we absolutely cannot have is a group of citizens who – because they did not like the outcome of an election, who did not believe the law was followed as it should be – foment revolution,” District Judge Amit Mehta said before handing down the sentence. “That is what you did.”

“I dare say, Mr. Rhodes – and I never have said this to anyone I have sentenced – you pose an ongoing threat and peril to our democracy and the fabric of this country,” Mehta said.

The judge added: “I dare say we all now hold our collective breaths when an election is approaching. Will we have another January 6 again? That remains to be seen.”

Mehta said Rhodes, 58, has expressed no remorse and continues to be a threat.

“A seditious conspiracy, when you take those two concepts and put it together, is among the most serious crimes an American can commit,” the judge said. “It is an offense against the government to use force. It is an offense against the people of our country.”

Mehta on Thursday previously ruled that Rhodes’ actions amounted to domestic terrorism.

“He was the one giving the orders,” Mehta said. “He was the one organizing the teams that day. He was the reason they were in fact in Washington DC. Oath Keepers wouldn’t have been there but for Stewart Rhodes, I don’t think anyone contends otherwise. He was the one who gave the order to go, and they went.”

Rhodes was convicted of seditious conspiracy by a Washington, DC, jury in November in a historic criminal trial that was a test of the Justice Department’s ability to hold January 6 rioters accountable and validated prosecutors’ arguments that the breach of the Capitol was a grave threat to American democracy.

The seditious conspiracy charge has rarely been brought in the century and a half that the statute and its forerunners have been on the books.

Prosecutors had asked Mehta to sentence Rhodes to 25 years behind bars, and to apply enhanced terrorism sentencing penalties.

“This is terrorism,” prosecutor Kathryn Rakoczy said Thursday.

“It is not blowing up a building directly or telling someone to blow up a building, but in light of the threat of harm and historic nature of attempting to stop the certification of an election for the first time in American history,” Rhodes and other Oath Keepers leaders should be punished more harshly, she said.

Rhodes, who was accused of leading dozens other individuals in a coordinated plot that culminated in the January 6 siege, was also found guilty of obstructing an official proceeding and tampering with documents.

Of those that Rhodes led, 22 have already been convicted of various federal crimes by a jury or guilty plea. Eight, including Rhodes’ codefendant Kelly Meggs who will be sentenced later Thursday as well, were convicted of seditious conspiracy.

Rhodes repeats false allegations about 2020 election

Rhodes, before he was sentenced, said he was a “political prisoner” and vowed to continue to “expose the criminality of the regime” in prison.

“I’d like to start by just saying that I’m a political prisoner, and like President Trump, my only crime is opposing those who are destroying our country,” Rhodes told Mehta in court.

For 20 minutes, Rhodes relitigated allegations that the 2020 presidential election was unconstitutional and shouted that he was “not able to drop that under my oath” during his military service and “not able to ignore the Constitution.”

The leader repeatedly defended his and his followers’ actions on January 6, saying that “no Oath Keeper took part in any of the fighting” and that the violence at the Capitol was “all done by other people.”

“I believe this country is incredibly divided, and this prosecution – not just mine but all the J6ers – is making it worse,” Rhodes said.

He continued, “I believe every J6er is a political prisoner and all of them are being grossly overcharged. It is going to make people feel like this government is even more illegitimate than they did before.”

This story has been updated with additional developments.

Oath Keepers leader Stewart Rhodes sentenced to 18 years in prison for plot to keep Trump in power