And "Mitt" rhymes with "bullshit"...
You don't have to take my advice, Mr. Romney (although Jim Gilmore didn't take my advice, and look what happened), but if you ask me, you played this one totally wrong.
For those who didn't click on the link, Romney has an arm around a fan holding a sign that says "No to Obama, Osama, and Chelsea' Moma (sic)". (He's also holding the sign up in another picture). His response to complaints was basically "I didn't see the sign, I don't remember what it said, and you need to lighten up." OK, if you didn't see the sign, why are you so defensive? Just say "I don't remember the sign, obviously I don't agree with it." You're done. Or, if you want to use the "best defense is a strong offense" line, you say "I thought it was a funny little joke, and nothing more, get a life." But this is the worst of both worlds; you want to play the persecution card a la Imus but you also foist the responsibility for the words on someone else.
Also, it makes you look like a liar. My guess is (and this is only because the following scenario is a million times more plausible than your excuse) you saw the sign, thought it was funny, didn't want to upset one of your radical supporters, and snapped a picture thoughtlessly, not thinking that in the age of interwebs and e-tubes it would show up on the news.
So, in a situation that could have been handled either with a sincere apology or righteous anger, you end up looking like a liar, a weasel, and a fool.
On the plus side, nice tan.