While true, it was the final straw in the wind of the perfect storm. There were lots of other factors, no one of which was The One reason we got The One. Not the least of these was a media in the tank for The one. That's really hard to overcome, since a great communicator like Ronald Reagan, who is also conservative, doesn't come along more than once in a few generations.
Obama was the one Democrat who could have lost, and McCain was the one Republican who could have won.
But it was a bridge too far.