My own response is below.
Your argument is disingenuous. Obama's "character" attacks, as you deem them, are a direct critique of the kind of Rovian campaign Clinton has run. Your Bin Ladin ad, on the other hand, continues your campaign's "3 a.m. theme" that Obama is unfit to be commander-in-chief. That's the kind of unfounded but resonant assertion that undermines a same-party rival -- in this case, the party's likely nominee.
Obama has repeatedly asserted unequivocally that Clinton would be far preferable to McCain as President. Clinton has reciprocated only under duress -- and continues to strongly imply otherwise on the most visceral issue of all, national security.
Moreover, Clinton's claim to have 'crossed the commander-in-chief threshhold' -- presumably hand-in-hand with John McCain while Obama lingers on the 'untested' shore -- is based in large part on exaggerations of her record epitomized by the Bosnia sniper fiction. Obama's rebuttal -- of this and other Clinton untruths -- does necessarily imply a character issue. I
When the Clintons have distorted Obama's record, he's called them out on it (as in the Jan. 21 debate, when he said that both Hillary and Bill have said things about his record "that are not factually accurate"). He's then made the point that such distortions undermine voter trust and so make it impossible to build the kind of working majority that can effect real change. To call that critique a 'character attack' is to persist with the kind of distortion that characterizes the Clinton campaign.
Your campaign is in fact a self-inflicted character attack. Sixty percent of Americans believe that Hillary cannot be trusted to tell the truth. That is why she will never be President.