In a surprise appearance before reporters at the White House just now, Obama made a striking, if perhaps long overdue, charge: He pushed back on GOP claims he’s running a dirty campaign by arguing that Romney’s entire campaign is based on flat out lies.

Obama was questioned sharply by a reporter who pointed to the Priorities USA ad featuring the dead woman and the Obama campaign’s pressure on Romney to release his tax returns, and asked whether he regretted his campaign’s tone. Obama responded, in part:

“I don’t think that Governor Romney is somehow responsible for the death of the woman that was portrayed in that ad. But keep in mind, this is an ad that I didn’t approve; I did not produce; and as far as I can tell, has barely run. I think it ran once. Now, in contrast, you’ve got Governor Romney creating as a centerpiece of his campaign this notion that we’re taking work requirement out of welfare. Which every single person here who’s looked at it says, it’s patently false...

“Everybody who’s looked at this says what Governor Romney is saying is absolutely wrong. Not only are his Super PACs running millions of dollars worth of ads making this claim; Governor Romney himself is approving this and saying it on the stump. So the contrast I think is pretty stark. They can run the campaign that theyw ant; but the truth of the matter is, you can’t just make stuff up. That’s one thing you learn as president of the United States. You get called into account.”

I’m pretty sure this is the first time Obama himself has charged that virtually Romney’s entire campaign is based on a “centerpiece” that’s flat out false.