Likeability numbers can change quickly and once the Convention is over and the air waves are flooded by Romney ads, some with his wife and perhaps his children occasionally they will change. Meanwhile Obama’s likeability numbers are dropping while Romney's have stabilized and there id not much more sleaze the Left can come up with which will not be viewed as totally over the top and inappropriate as the Coptic ad and the charges about his taxes (Unfounded) and now the “link” to Salvadoran Death Squads.
Sorry but I see the media spinning like crazy to prop up Obama and while there are plenty of ignorant people in America there are not that many who cannot see what Obama is about after almost 4 years. In 2008 they painted him with their own dreams and saw what they wanted to see. It's 2012 now and the paint has faded and cracked and no Earl Sheib quick paint over will fool any substantial amount of people.
Kerry’s response or non response to Swift Boat probably would not have affected things either way.His belated response did wha an early response would have done- brought up more testimony and more evidence against him. If the charges are false you refute them forcefully once, echo it briefly once or wice and go on to atack, of better, do what Reagan did. You put forward three +- BIG things you intend to accomplish and hammer on them without much responding to attacks, except humorously. But first, you have to have big things you want to accomplish and have to know how to put the goals into a few forceful words with occasional explanations for side play. Romney has no understanding of that sort of thing at all. He is more of an accountant who wants to get the details right, whatever might be the big picture.