A judge on Thursday handed down the longest prison terms so far in the plot to kidnap the Democratic governor of Michigan, sentencing three men who forged an early alliance with a leader of the scheme before the FBI broke it up in 2020.

Joe Morrison, Pete Musico and Paul Bellar were not charged with direct roles in the conspiracy but were members of a paramilitary group that trained with Adam Fox, who separately faces a possible life sentence on 27 December.

The trio were convicted in October of providing material support for a terrorist act, which carries a maximum term of 20 years, and two other crimes.

Musico was sentenced to a minimum of 12 years in prison, followed by his son-in-law Morrison at 10 years and Bellar at seven. They will be eligible for parole after serving those terms.

In a recorded video, the governor, Gretchen Whitmer, urged the judge to “impose a sentence that meets the gravity of the damage they have done to our democracy”.

“A conspiracy to kidnap and kill a sitting governor of the state of Michigan is a threat to democracy itself,” said Whitmer, adding that she now scans crowds for threats and worries “about the fate of everyone near me”.

The judge, Thomas Wilson, presided over the first batch of convictions in state court, following the high-profile conspiracy convictions of four others in federal court.

Fox and Barry Croft Jr were described as captains of an incredible plan to snatch Whitmer from her vacation home, seeking to inspire a US civil war known as the “boogaloo”.

Whitmer, recently elected to a second term, was never physically harmed. Undercover FBI agents and informants were inside Fox’s group for months and the scheme was broken up with 14 arrests in October 2020.

A person convicted of more than one crime in Michigan typically gets prison sentences that run at the same time. But Wilson took the unusual step of ordering consecutive sentences for Musico and Morrison, making their minimum stays longer.

In addition to being convicted of supporting terrorism, the three men were each convicted of a gun crime and of being a member in a gang.

Musico, 45, Morrison, 28, and Bellar, 24, were members of the Wolverine Watchmen. The three held gun training with Fox in rural Jackson county and shared his disgust for Whitmer, police and public officials, especially after Covid-19 restrictions disrupted the economy and triggered armed Capitol protests and anti-government belligerence.

But defense attorneys argued that the trio cut ties with Fox before the Whitmer plot came into focus by late summer 2020. Bellar had moved to South Carolina in July. The three men also didn’t travel with Fox to look for the governor’s second home or participate in a key training session inside a “shoot house” in Luther, Michigan.

“Mr Bellar is clueless about any plot to kidnap the governor,” the attorney Andrew Kirkpatrick said in a court filing last week.

A jury quickly returned guilty verdicts in October after nine days of testimony, mostly evidence offered by a pivotal FBI informant, Dan Chappel, and federal agents.

Separately, in federal court in Grand Rapids, Fox and Croft face possible life sentences in two weeks’ time. Two men who pleaded guilty received substantial breaks: Ty Garbin is free after a two-and-a-half-year prison term while Kaleb Franks was given a four-year sentence.

Brandon Caserta and Daniel Harris were acquitted by a jury.

When the plot was foiled, Whitmer blamed then-president Donald Trump, saying he had given “comfort to those who spread fear and hatred and division”.

In August, after 19 months out of office, Trump said the kidnapping plan was a “fake deal”.