Abe Lincoln ran with the slogan: "Don't swap horses in the middle of the stream"
I'm willing to bet that Obama and crew will be running with a similar slogan in 2012 with the view that the work isn't finished yet.
If I was Sarah, I would start work right now on dismantling that theme - refer to it as 4 more years of Bush if you have to - but destroy it early on and build on it.
People need to look upon 4 more years of Obama with horror. I do.