[he can no longer convince the general public that Romney is a good debater]
Actually, Romney is a great debater, one of the best. If you mean at the high school or JC level where you are called on to take a side at random.
Romney himself believes in nothing but expediency, his lack of conviction oozes out of each sentence. Newt may be a flawed human, but one reason he comes over forcefully is he believes what he is saying. Ditto Perry, Santorum, even Paul.
If we were electing a used car salesman, Romney would do just fine.
There was once another portly, over-the-hill, former politician, that drank too much. They said his finest days were behind him. His name was Winston Churchill.