Nine men have been convicted or pleaded guilty, and two others were previously acquitted.

Prosecutors say the plot was motivated by rumours that the 2020 presidential election would be stolen and opposition to Covid-19 restrictions imposed by Ms Whitmer's administration.

The group, which included members of the Wolverine Watchmen militia, planned to stage a "trial" of the governor for treason and hoped the kidnapping would spark a larger conflict.

Ringleaders Adam Fox and Barry Croft Jr were convicted of kidnapping conspiracy last year. Fox was sentenced to 16 years in prison while Croft was handed a sentence of 19 years and 7 months. Joseph Morrison, the leader of the Wolverine Watchmen, was sentenced to 10 to 20 years in prison.

But the jury acquitted the Nulls and Mr Molitor, who were the last to stand trial in connection with the case, after a three-week trial in Antrim County in northern Michigan, site of Ms Whitmer's holiday home.

During closing arguments on Wednesday, prosecutor William Rollstin said the men "hated their government" and "were willing to go to war".

Prosecutors said the Nulls - who are twin brothers - and Mr Molitor participated in military-style drills and travelled to Ms Whitmer's holiday home, where they shot a reconnaissance video.

In testimony, Mr Molitor and William Null admitted they had attended drills and travelled to the holiday home. But the defence argued that the trio were scared off when talk turned to violence and did not support the plot. Mr Molitor said Fox, one of the organisers, was "incredibly dumb" and would not pull off a kidnapping.

In closing arguments Mr Molitor's attorney, William Barnett, said that prosecution case was "weak".

"They're here pulling the shortcuts to try to get somebody convicted, an innocent person," he said.

The defendants gasped with relief and sobbed as the verdicts were read out, then embraced their supporters in the courtroom.

After the verdict Mr Barnett told local reporters: "These charges shouldn't have been brought and justice has been served."

Undercover FBI agents had monitored the group for months before arrests were made in October 2020, a month before that year's presidential election.

The plot was never carried out, and Ms Whitmer was not harmed.

The case became a significant talking point during the 2020 election over the threat posed by domestic terror groups. Ms Whitmer was criticised by Donald Trump and conservatives for imposing a Covid lockdown in Michigan in spring 2020. In late April of that year, armed protesters entered the Michigan state capitol building.

"Today's verdict is disappointing," Ms Whitmer's chief of staff JoAnne Hulls said in a statement. "A not guilty verdict on the plot to kidnap and kill Governor Whitmer in hopes of starting a civil war will further encourage and embolden radical extremists trying to sow discord and harm public officials or law enforcement."

But Michigan Attorney General Dana Nessel, whose office prosecuted the case, said the previous convictions of other members of the group "sends a clear message that acts of domestic terrorism will not be tolerated in our state".