Bush had a far higher approval rating among all of the nation as well as among his party during the election cycle for his second term. Ignoring this and pretending that all Rs are on this guy's bandwagon when it is clearly not true is still more pretense. It isn't going to convince anybody that all Rs follow Bush or that all Ds will follow Carter. However there was a significant percentage that will vote D or R regardless of who the person running is.
I'm not saying there isn't a certain % that will only vote for dems. I'm saying the number is bigger on the con side and the liberal constituency is more likely to react to leaders that go astray. Other than indicted republican's, I haven't seen the con's constituency react much at all. The "far-left" as I would be deemed, is moving away from Hillary and Lieberman lost his primary.