If McCain does happen to get the GOP nod, he will move leftward to gain more Independents and Liberals. [He abandoned the real conservatives along time ago, and chances are, he won’t be able to regain their confidence and votes.]
Ironically, if Clinton does get the Dem nod, she will move rightward to gain more Independents and Moderates.
They could pass each other, politically. By November, McCain could show up as the liberal and Clinton as the conservative.
If McCain was the nominee and Obama bet Hillary, It would not surprise me to see McCain and Hillary team up to run against Obama and his running mate!