Due Diligence: An unfair attack on Mitt Romney

(CBS News) A Democratic-aligned video out this week ties Mitt Romney to the death of a woman whose husband's plant was closed by Bain Capital, the company Romney used to run.

The video comes from Priorities USA Action, an outside group backing President Obama. It features a steelworker who says his wife died from cancer after Bain Capital closed the plant where he worked.

"When Mitt Romney closed the plant I lost my health care, and my family lost their health care," the man says in the spot. "And a short time after that, my wife became ill. I don't know how long she was sick and I think maybe she didn't say anything because she knew we couldn't afford the insurance."

The story is certainly affecting, and it fits into the Obama camp's narrative that Romney doesn't care about working people. There's just one big problem: It's not true.

CNN spoke to the steelworker, Joe Soptic. He acknowledged that his wife had gotten her primary insurance from her own job, a job she held after Soptic was laid off. She eventually had to leave that job, and got sick a few years after that - five years after the plant was closed. The suggestion in the ad that there is a direct line between the plant closure and Soptic's wife's death is inaccurate and unfair.

Priorities USA Action can legally have no connection to the Obama campaign. But like many similar groups, it's overseen in part by someone with close ties to the candidate it supports - in this case, former Obama White House spokesman Bill Burton.

The new ad is the latest to raise questions about whether super PACs and campaigns are engaged in tacit collusion - the super PAC runs nasty ads like this one to inflict damage on an opponent, while the campaign (not entirely plausibly) maintains its innocence. Consider: Soptic has appeared in a previous Obama campaign ad, and the campaign itself shared the story of Soptic's wife with the press back in May. On Wednesday, senior Obama campaign adviser Robert Gibbs refused to condemn the ad, telling MSNBC that he isn't familiar with the specifics of it. But he did endorse the message.

"This is an ad by an entity not controlled by the campaign. I certainly don't know the specifics of this man's case," he said. "I do think there is a lot of concern in the country about what happens when people lose their jobs -- we know that when they lose their jobs, because of most of where people get their healthcare provided for is in their jobs, they do also lose their healthcare."

White House press secretary Jay Carney said he hadn't seen the ad, and thus couldn't comment on it. But he also made clear he isn't going to weigh in. Instead, the White House has pressed reporters to focus on another inaccurate ad out this week - a Romney campaign attack on President Obama over welfare.

But bad behavior by the Romney campaign does not excuse an unfair attack from Obama's backers. And the Obama campaign's refusal to disavow the spot speaks to just how nasty the campaign has already gotten - a full three months before Election Day.

Thanks for watching.