You know, Kerry’s voters may or may not have been passionate, but they also turned out in huge numbers. 2004 was a huge turnout election and I believe 2008 will be very similar. I believe that Kerry’s vote total in 2004 would have been the highest ever for a Presidential candidate — except for Dubya’s even higher total.
The problem with Obama right now is that everything he does seems to be geared towards firing up his base voters rather than swing voters and undecided voters. McCain picked Palin in part to secure his own GOP base, leaving him free to go agressively after these voters (Of course, Palin aso has great appeal to these voters as well). And he was winning those voters handily until the financial turmoil hit. But this may be nothing more than a temporary speed bump. There is evidence from other contemporaneous polls that the electorate is now swinging back to McCain.
"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus