Twin brothers William and Michael Null and a third man, Eric Molitor, were found not guilty of providing support for a terrorist act and a weapons charge on Friday, according to the Associated Press.
They were the last of 14 men charged over the militia kidnapping plot on the eve of the 2020 presidential election. Nine others have been convicted.
Prosecutors had alleged that the Null brothers and Mr Molitor had participated in the scheme by taking part in military drills and travelling to governor’s lakeside vacation home in Elk Rapids, in northern Michigan.
The trio were portrayed as anti-government extremists who were angry with Ms Whitmer’s decision to close down schools and businesses during the Covid pandemic.
The plotters were being secretly monitored by the FBI for months, and were arrested in October 2020 before they could carry out the plan.
Mr Molitor, 39, and William Null, 41, testified that they had taken part in drills and admitted going to Ms Whitmer’s home, but said they backed out of the group when members discussed obtaining explosives, according to the Associated Press.
Michael Null, also 41, refused to give evidence and his lawyer declined to answer questions of any of the trial witnesses.
Plot ringleaders Adam Fox and Barry Croft Jr were convicted of federal kidnapping conspiracy at a trial last year.
Fox was sentenced to 16 years in prison. Croft received a sentence of 19 years after being found guilty on charges of kidnapping conspiracy, conspiracy to use a weapon of mass destruction and possessing an unregistered destructive device.
Two other men, Brian Higgins and Shawn Fix, pleaded guilty earlier this year in exchange for reduced charges and agreed to cooperate with the prosecution.
After the kidnapping plot was foiled by the FBI, Ms Whitmer placed the blame for the failed scheme squarely on the shoulders of then-President Donald Trump.
“Hate groups heard the president’s words not as a rebuke, but as a rallying cry,” Ms Whitmer said at the time.
“When our leaders speak, their words matter. They carry weight. When our leaders meet, encourage or fraternise with domestic terrorists, they legitimise their actions and they are complicit. When they stoke and contribute to hate speech, they are complicit.”