In the last ten presidential elections, Montana has show it's left leanings only once: in 1992, when it voted for then-Gov. Bill Clinton over President George Bush.
McCain's story, military service and ties to the Western regions of the country will likely resonate with Montana conservatives but Obama's efforts in the state have been consistent.
Obama won Montana's Democratic primary by a margin of 57 percent to Sen. Hillary Clinton's 42 percent in June and clinched his party's presidential nomination when the state's delegates were added to his tally.
On his fourth visit to the state over July 4, Obama spent the holiday in Montana campaigning with his family and has launched an aggressive advertising campaign there.
The National Rifle Association recently took the charge against Obama in Montana, characterizing the Illinois senator as a threat to gun owners in the state.