Really, I don't see this as an offer to Fred. I see this as a very diplomatic answer by Mitt that he would not automatically exclude Fred. The same words could be used to imply that he would consider Obama as a running mate .
I agree. This was a normal, polite answer to a specific question. What he was supposed to say? “Nah, he is the last guy I would consider”?
Frankly, there is zero chance of Fred being a VP candidate for Romney. Romney’s campaign message is “Washington is broken” and he has been railing against A) Washington Senators, B) Lobbyists. Fred Thompson’s background as a Washington Senator and lobbyist would not fit too well to Romney’s campaign..
Besides, Fred didn’t want to campaign even for himself. Why would he want to campaign for somebody else? I think the nominee (whoever he is) wants to have energetic and young(ish) candidate who is available 24/7 (Obama and Hillary surely are) and has good media skills.
Probably Romney would pick a strong conservative with a proven executive record, or really a clear outsider choice (such as former MD Lt.Gov Steele who is a great communicator and african-american).
McCain cannot pick Thompson either. He would really need a young and energetic VP.
Romney will probably pick Rudy or someone similar.