By Max Deveson
BBC News, Bangor, Maine
It has long been a liberal bastion, voting solidly Democrat in every presidential election since 1992.
In north Maine residents enjoy moose-hunting, fishing and snowmobiling
But both of Maine's senators are Republicans, and the appearance of Sarah Palin on the Republican ticket could be giving plenty of voters pause for thought.
Last week the McCain campaign upped its advertising spending in the state, and on Thursday, Mrs Palin herself is visiting Bangor - the biggest town in Maine's second congressional district - with her husband Todd, a snowmobile race champion whose renown extends beyond Alaska.
The southern and coastal regions of the state are certain to vote for Barack Obama.
In the north of the state, however, residents enjoy moose-hunting, fishing and snowmobiling just as much as they do in Mrs Palin's home state of Alaska.
"We are very impressed with the McCain-Palin ticket," said Paul Davis, president of the Maine Snowmobile Association.
"I think Sarah Palin has made the second district of Maine a battleground out of what most likely was an open-and-shut case for Obama."
It just so happens that Maine is one of two US states - the other is Nebraska - that do not operate a winner-take-all system in the presidential election.
The candidate who wins the northern second congressional district will carry away one of the state's four electoral college votes.
This partly explains why, when John McCain announced he was giving up the battle for Michigan he added that he would be transferring some resources to Maine.
The withdrawal from Michigan effectively signalled the end of any Republican hopes for a landslide victory - and in a close race every electoral college vote counts.
The visit of Sarah Palin is exciting Republicans.
"Sarah and Todd's visit could be enough to swing it for us," said Nick Dagher, 36, a first-time Republican volunteer in Bangor.
"The moment Senator McCain picked Sarah Palin, the number of volunteers - especially professional women - just exploded," Mr Dagher added.
One of those professional women, 33-year-old insurance agent Jenny Schnedler, busily working the phones to Piscatiquis County, in the north-west of the state, said she was confident the message was "getting through".
It's rural areas that are the best hunting grounds for the McCain volunteers - which may explain why their office, with the air of a down-at-heel call centre, is located on the outskirts of the city.
Jobs and college kids
The Obama headquarters, by contrast - which resembles a college dormitory, with handmade posters lining the walls - is right in the centre of town.
The volunteers there were also upbeat.
Anne Borregine, a veteran of Democratic presidential campaigns since 1980, said she had "never experienced so much energy at the grassroots".
Her fellow phone-basher, Meghan Baldridge, was dismissive of the McCain camp's decision to concentrate resources in Maine's second district.
The walls of Obama headquarters in Maine are lined with handmade posters
"If he wants to waste his money for one electoral vote, then good luck to him," she said.
"We'll gladly take Michigan."
Former Maine Senator George Mitchell, passing through Bangor on a tour of the state to drum up support for Barack Obama, said the decline of the local economy during the Bush years made a Democratic victory highly likely.
"During eight years of Bill Clinton, 98,000 jobs were created in Maine," he said. "Under George W Bush, just 5,000 have been created."
In the Van Raymond Outfitters, a hunting and fishing store in Brewer, Maine, opinion was divided.
"A lot of folks who come in here were already going to vote for John McCain," said manager Rick Lozier.
"I couldn't say whether she's made a difference, but I like her."
But his colleague Jim said he doubted Mrs Palin was intellectually up to the job.
In the balance
In the last three state-wide polls conducted in Maine, Barack Obama held a four or five point lead over his Republican rival.
Polling analyst Nate Silver projects that Mr Obama will poll two or three points below his state-wide vote in the second district, which is home, as his colleague Sean Quinn puts it, to "most of the places where people die in Stephen King novels".
So if the polls stay static, or the race tightens at all, then the second district's electoral vote may really hang in the balance.
There is more than one plausible scenario for election day on 4 November, where the two candidates could end up with 269 electoral college votes each.
In that case the hunters, fishermen and snowmobilers of northern Maine could play a decisive role.