Montana is typically safe territory for Republican presidential candidates. President Bush won the state by about 20 points in both 2000 and 2004, and only two Democrats - Lyndon B. Johnson in 1964 and Bill Clinton in 1992 - have carried the state since 1948.
But Obama staked out Montana early as a potential battleground state and he's sticking with it to the end. McCain, confident of winning the state's three electoral votes, is virtually ignoring it, although the Republican National Committee will begin airing ads in Montana for the first time Wednesday.
Obama's campaign didn't back off when the state appeared to be a shoo-in for McCain in September. And now McCain's lead appears to be in doubt. A recent Montana State University-Billings poll showed the race within the margin of error, with Obama at 44 percent and McCain at 40 percent among likely voters, and 10 percent undecided.
Obama's rise may be less about his appeal and more about dissatisfaction with McCain among independent-minded voters.
The Democratic presidential hopeful was the beneficiary of support for Constitution Party candidate Ron Paul. Paul is not campaigning - he even asked to be taken off the ballot - but some supporters still say they will support him over McCain.
Obama also has been advertising in the state at a rate of about $160,000 per week. The Republican Party was expected to double that ad buy for the last six days of the campaign.
Up in the Kalispell area, more than 30 percent voted for Paul in the June primary - well after it was clear McCain was the party's presumptive nominee. Many will vote for him again, said avid supporter and AM radio talk show host John Stokes.
"People are just fed up with the mainstream parties," Stokes said. "Folks see this country is on a downward slope and not adhering to the Constitution."
Paul garnered 4 percent of the vote in the recent poll, although he has not made an appearance in the state and has no office or volunteers.
McCain's campaign has never considered Montana a battleground state and still doesn't. His campaign has no paid staff in the state but operates out of six offices it jointly runs with the Montana Republican Party, which staffs them.
McCain is banking on the advice of state Republicans who told him to focus on more competitive states.
"John McCain has basically punted in Montana," said veteran pollster and political scientist Craig Wilson, who oversaw the MSU-Billings poll. "But I am still surprised that Obama is still playing to the extent he has in Montana."
That has left the state open for Obama to make his case. His campaign has been buying television ads for months, with no plans to scale back.
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Still, Ethan Heverly, a University of Montana college student organizing for the McCain campaign, believes McCain will carry Montana despite the lack of paid organization in the state. Gun groups are helping with a strong push against Obama, while the addition of Gov. Sarah Palin to the GOP ticket is helping energize the base, he said.
"I think that, for the most part, he identifies better with Montana values and Montana voters than Sen. Obama does," Heverly said. "It's definitely competitive, I'm not going to lie to you."
The volunteer believes Obama's large organization is making it close but thinks McCain is doing the right thing to focus elsewhere.
"If Montana can stay red and we can allow Sen. McCain to focus his money elsewhere and be competitive in the larger states, I think that's a plus," Heverly said.
In its bid for Montana, the Obama campaign has seized on Western issues and developed nuanced platforms for farm, wildfire and natural resource policy.
But the McCain campaign says Obama is too liberal for places like Montana and believes that in the end voters in the state will embrace the Republican.
While the GOP has history on its side, Democratic Gov. Brian Schweitzer gives several reasons this year is different: Obama has been here five times to ask for votes; he is pitted against a Republican who does not excite conservatives on key issues like guns; and Obama has articulated a comprehensive energy policy.
Guns are an important issue to Montanans, and Democrats like Schweitzer and Sen. Jon Tester, who ousted longtime GOP Sen. Conrad Burns, score high with gun owners. Obama has tried to neutralize the issue by saying he won't take away guns.
But that hasn't eased the fears of influential groups like the National Rifle Association, which has lashed out at Obama as "a poster child of the extremist, elitist gun-control movement."
In years past, Montana rarely received attention from presidential candidates. And if it did, the state never received the committed attention it has from Obama.
The Obama campaign says it has no plans to pull resources from Montana, where it has 19 offices with full-time staff across the state. The campaign boasts 14,000 active volunteers, according to Caleb Weaver, Obama's spokesman in the state.
Obama's ties to Montana go beyond his numerous visits this season. His campaign chief of staff, Jim Messina, previously worked for Montana Sen. Max Baucus. Messina has promised the campaign will spend whatever it takes in Montana to ensure Obama is competitive with McCain.