Maybe not, says Ezra Klein:
[P]erhaps Obama would be winning this in a rout if Romney didn’t have a money advantage. And perhaps the Romney campaign will dump enough money on Obama’s head in the final month or so that it will have a real and measurable impact in the polls. You can’t rerun the past, and I don’t have much information about the future. But for now, Romney’s money advantage has not yet proven decisive.
Nate Silver, on the other hand, sees some possible movement in the swing states:
I don’t think we should totally write off the idea that Mr. Romney has made up some ground in the swing states. Apart from his selection of Mr. Ryan, there are other things going on in the campaign. For example, Mr. Romney’s advertising advantage in swing states could be starting to pay dividends.