The most interesting paragraph in this Public Policy Polling report on Montana is the penultimate one:
Montana's a state where Gary Johnson may have a bigger impact than other places. When he's included he polls at 7% and since he pulls more from Romney than Obama he pushes Mitt's lead down to a 46-43 margin. Montana hasn't received the kind of attention it did in 2008 as a state that Obama could possibly win, but it looks like he's at least headed for a competitive loss there again this time around.
If enough Republicans are disgusted with Romney by election time and if enough Ron Paul voters turn out for Johnson, there's a possibility that a few of the blood-red western states might wind up being competitive for President Obama.