Romney in the one most relevant. BO has a mediocre approval rating - Romney had a decent (not good) message, but he still lost.
I have to wonder if that was because he did not energize the conservative base, did not attract enough traditional votes (I.e. married women) or what
Because he was a FAKE ringer candidate for the party establishment. Willard was there to assure no Conservative got near the GOP nomination and to make sure Zero got a second term.