In his glory days as heavyweight champ, Muhammed Ali perfected a technique known as the "rope a dope" in which he would allow an opponent to repeatedly punch him in the mid-section while Ali guarded himself against the ropes. Then, when the opponent tired from punching Ali, the champ would move in for the kill and finish off his winded opponent. This was a great strategy for boxing. It is a sure loser in politics.
Unfortunately, Obama seems to have adopted the "rope a dope" strategy in dealing with McCain's attacks. Obama's erosion in the polls (whether or not the latest Zogby is accurate) is a predictable result. If he is waiting for McCain to punch himself out, he can expect to be returning to the Senate in January 2009.
Negative campaigning is particularly effective if the other side does not fight back. The only strategic reason for politicians to avoid negative attacks is the fear that the opponent will fight back in kind. It is true that a negative attack may drive a politicians favorability rating down but as long as your opponent's numbers go down more, than it is a success. But, if your opponent then goes negative, your ratings may go down more. This is a very simple principle. It's called deterrence. It's why nuclear weapons haven't been used and why poison gas wasn't used in world war two. The only way to stop McCain's negative attacks is to fight back. Otherwise, he gets a free ride (has there ever been an election where anyone lost a substantial number of votes just because there was a backlash against negative attacks?). McCain in fact, has a figurative glass jaw, but it is up to Obama to fight back.
Ironically, Obama's refusal to fight back only plays into an un-stated but obvious sub-text in McCain's messages, that Obama is not tough enough to be president. By fighting back and going on the attack, Obama re-enforces his own toughness. There is enough real material that Obama need not be worried that he will be perceived as delivering cheap shots (although he certainly will be accused of it). Because of Hillary Clinton's unique position as the only woman in the race, there may, in fact, have been some valid reasons for a reluctance in going negative during the primaries, apart from the obvious fact that she was a member of his party, who he would have to support in the general election. These considerations do not apply to a general election campaign against McCain. In fact, the more that McCain complains about perceived "negative attacks" against him the less tough he appears and the more he appears to be sanctimonious and arrogant, traits which the electorate tends not to like.
So, Obama needs to stop being reluctant to criticize McCain or his motives. Yes, McCain was a POW. This does not make him either a good person in all respects or intellectually gifted. (Remember friends, Charles Lindberg was a hero aviator but would have been a disaster as president-but I digress). Obama should call out McCain for being Un-American. Why? Because there's nothing more Un-American than questioning someone's patriotism based on their ethnic background. Let McCain deny that he's doing that. There are, of course, many other obvious attacks. Phil Gramm returns to the campaign. McCain thinks the Iraq war was a good idea and that Iraq borders Afghanistan.. McCain thinks the economy is fine and Bush's policies are great, etc.
Rightly or wrongly, every time Obama refuses to fight back in kind he re-enforces the perception that McCain is tougher than he is. People want a tough president. If Obama doesn't go after McCain, he will be picking himself up off the canvas in November