I'm not sure that the two are exclusive. In the debates, I'd like to see the President go after Romney on his multiple positions. With his mastery of detail, I'd love to watch as Mr. Obama says, "But Governor, in 2002 you said that you would support a woman's right to choose." "Governor, in 1996, you said that we had to assure equal rights for gays and lesbians." "In 2008, you said that you didn't think that hunting down one man--you meant Osama bin Laden--was all that important." "In 2008, Governor, you wrote an op-ed piece in The New York Times that was titled, 'Let Detroit go bankrupt.'" "Governor, given all of your changes of position--some of them several times on the same issue--how can the American people trust what you are saying now?"
The conventional wisdom is that the President should take the high road, that he should let his aides and surrogates (and the Vice-President) attack the other candidate. That's exactly why Mr. Obama should look for chances to expose Mitt Romney in the debates for what he is: a thoroughly unprincipled man, consumed by the quest to be elected President, but with no principles to guide him should that happen. For one thing, that approach would be unexpected and likely to through Romney off balance. For another, it would give voters the clearest opportunity to see the difference between the two men's characters. And, Democrats could still brand Romney as an apostle of the right by suggesting that his (many) other positions are simply cover.
Yes, such an approach would be less focused than Clinton's advice, but above all, Americans need to feel that they can trust their President.