This McCain supporter wishes he had a clue, but really does not. No one stands out, really, as to my personal preference, as opposed to what is the most politically expedient preference, assuming we are putting that consideration aside, and ignoring electoral realities. Maybe chief justice Roberts if he were willing to take a rather drastic demotion. He's smart of course, and highly articulate, and has charm, and is of the right age.
That would create all types of problems, not just from ther perspective of having the CJ run for VP. He's had those seizures, which would create some doubts.
