*Update: Phil Scott and Sue Minter won their respective primaries and will face off in November.

Vermont Republicans are hoping that history will repeat itself. Since 1968, every time the governorship has been left open by retirement, it's been taken over by the other party.

Democratic Gov. Peter Shumlin, who was nearly defeated in 2014, decided not to run again. And even though Vermont is one of the bluest states in the nation, the GOP is optimistic about its chances this fall.

One big reason is Phil Scott, Vermont's lieutenant governor. Scott is an almost universally well-liked personality in the state and is just the sort of moderate Republican who can still win in New England. But first he has to get through Tuesday's GOP primary.

His opponent is Bruce Lisman, a former Wall Street executive. Lisman has no prior government experience, but he has spent so freely on the campaign that the primary will be less of a coronation for Scott than originally expected.

"Lisman is on track to spend what I think will be $100 per vote," said Eric Davis, a retired Middlebury College political scientist. "He'll have spent more than anyone per vote in the history of the state, and more than almost anyone in the history of the country."

The situation remains murkier on the Democratic side. A total of five candidates are running, but only two have a real chance at this point: Matt Dunne, a Google executive who has served in both chambers of the state legislature, and Sue Minter, a former legislator who served in Shumlin's cabinet as transportation secretary.

As expected in Bernie Sanders' home state, the Democratic frontrunners have each taken liberal positions on a number of issues, such as increasing the minimum wage and offering free or reduced tuition for college students.

"They have to come out in favor of some of these proposals Sanders has pushed," said Bert Johnson, another Middlebury College political scientist.

The question is whether the Democratic nominee will have taken policies that are too progressive, even for Vermont. Both Dunne and Minter have called for universal background checks for gun purchases. In a rural state where crime is not much of a problem, the idea of passing restrictions on guns is rarely discussed, let alone formally debated in the legislature.

"Gun control has not been a winning issue for Vermonters," said Rich Clark, director of the Castleton Polling Institute. "We saw Bernie struggle with it in the Democratic debates."

On the Republican side, Scott has stressed that he'll be cautious about launching pricey new initiatives. That could sit well with many Vermont voters -- even Democrats -- who may have grown skeptical about funding new programs or looking for government interventions, in light of the state's troubled health insurance exchange and abandonment of universal health care after spending lots of time and money on it.

Scott has also not associated himself with divisive social issues, and he said early on that he would not support Donald Trump for president.

Scott will be "the clear favorite to win the governorship," said Garrison Nelson, a professor at the University of Vermont.

Dunne, of Google, is making his third run for statewide office but has sought to position himself as the progressive outsider in the race. He took a blow recently after he released a statement saying that if communities voted against a major wind project, he "would use all the power of the governor's office to ensure that is the end of the project."

Wind energy is a contentious issue in Vermont, but what hurt Dunne most was the perception that he had flipped on the issue. That's a charge his campaign has denied, saying the statement was simply a "clarification" of his position. 

Dunne's statement, however, has cost him the support of environmentalists, such as Bill McKibben, who switched his endorsement from Dunne to Minter. Similarly, the group Vermont Conservation Voters endorsed Minter after having been neutral in the race. But it's not yet certain that Minter will come out ahead.

"I am not sure if the loss of environmental support will be enough to tilt the race to Minter. But in a low-turnout contest, anything is possible," said Nelson.

Minter has the backing of former Gov. Howard Dean and several dozen sitting legislators. She has won praise for helping lead the state's recovery from Hurricane Irene in 2011.

"My bet is that it is Scott and Minter" who win the primaries, said Clark.

Vermont voters have not shied from splitting their tickets. Vermont was one of President Obama's best states during both his runs for the White House. He carried the state with 67 percent each time. But Jim Douglas, the state's last Republican governor, won re-election easily in 2008, even with Obama at the top of the ticket.

"The idea that we are internally a completely blue state I think is overblown," said Clark.

Nevertheless, running as a non-incumbent Republican will be a bit of a tough sell during a presidential year. One big question looming over the race is how the presidential vote will go.

"Scott will need split-ticket voters in order to win," said Davis. "But if Hillary ends up getting 60 percent, he'll need a lot less than if she gets 70 percent."