Obama Leading McCain in Montana

How long until we hear the talking heads ask if Barack Obama has a cowboy problem? Rasmussen Reports has Obama up in Montana:

Barack Obama is leading John McCain by five percentage points in Montana. The latest Rasmussen Reports telephone survey in the state shows Obama attracting 48% of the vote while McCain earns 43%.
In April, the numbers were reversed with McCain leading 48% to 43%. That was before Obama clinched the Democratic nomination and defeated Hillary Clinton by fifteen points in Montana.
...
Against McCain, Obama leads among voters under 50, including a twenty-seven point lead among voters under 30. McCain leads among those over 50. Obama is supported by 89% of Montana Democrats while McCain gets the vote from 85% of Republicans.

How big a deal is this result?

It would be truly stunning if Obama could turn Montana into a competitive state this November. George W. Bush won Montana’s 3 Electoral College Votes by twenty percentage points in 2004 and by twenty-five points four years earlier. Even Bob Dole managed to win Montana, albeit by a narrow 44% to 41% margin (Ross Perot picked up 14% of the vote).

FiveThirtyEight.com gives Obama only a 16 percent shot of winning Montana. I'd say that number is likely to move a bit based on this result. (Update: 538 has boosted Obama's chances to 36 percent. Nate points out some interesting details in the poll.)
Atrios points out that Montana's governor and two senators are already Democrats.