So, did the Obama campaign decide to opt out of public financing because their offers to negotiate with the McCain camp over restricting outside ad spending were rebuffed?

That's what the Obama campaign's top legal adviser claimed in a conference call a few moments ago, as the skirmishing over Obama's decision dragged into the evening.

Chief legal counsel Bob Bauer insisted that he'd communicated their concerns at his meeting with McCain counsel Trevor Potter. Instead, Bauer says, Potter never answered their concerns -- and added that McCain has actually tacitly encouraged such 527s to gear up and go after Obama.

"It seems to me that if we scheduled this discussion," Bauer said, "and we put forward our concerns, and we heard nothing back, nor anything in the meeting that could in any way suggest that fruitful exchanges were productive, it isn't clear to me that the McCain campaign is in the position to accuse us of failing to negotiate."

Here's the audio from the call:

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