Both of them can credibly take the position of saying that any health-care plan, and especially any health-care mandate, must be state-based. A federalism argument may seem a copout to some, but the truth is that it can be made pretty clearly and convincingly in this case.
Obviously, I'd prefer if neither of them was ever on record as supporting a mandate on any level, and were pushing for reforms more along what Indiana has done. But the truth is that in a general election, saying this should be an issue that states and local people should decide for themselves is a still a winner, both in substance and politically.
1) Only John Kerry and Al Gore have him beat on flip-flopping. Romney's the type to run pro-life in a GOP primary and once he gets the nomination he'd run pro-abortion to win the democrat votes and somehow explain that he never changed his mind or flip flopped.
If there was a democrat majority in Congress he would nominate liberal judges and by the time his re-election comes up in 2016 he will claim that he had to nominate liberal judges in order to get them passed through the liberal Congress. That's Romney.
The other problem about Romney is that he's too "in your face" as a candidate. He could easily lose it in a debate and earn sympathy for Obama. We don't need that to be happening.