"What is new here is that the 'America Deserves Better' ad seems to score points for Romney," Ad Rating Project leader and Vanderbilt political science Professor John Geer told UPI.

"It was the first time among all the ads we have studied where a Romney attack moves down the president's numbers among pure independents," he continued.

The ad, which has aired in Iowa, takes the president to task over an ad cut by his super-PAC featuring the widower of a cancer victim. The man in the commercial was laid off of his job as a steelworker when the company he worked for was bought out by Bain Capital, and speaks about losing his health insurance. But Romney had left Bain at the time of the takeover, the woman carried her own insurance, and she was diagnosed with cancer some six years after her husband was laid off.

In the commercial, the Romney campaign criticizes Obama of trying "to use the tragedy of a woman’s death for political gain."

“What does it say about a president’s character when he had his campaign raise money for the ad, then stood by as his top aides were caught lying about it?” the narrator says. “Doesn’t America deserve better than a president who will say or do anything to stay in power?”

The president looked to distance himself from the ad during a press conference earlier this week, noting his campaign was not legally allowed to coordinate with the super-PAC.

“I don’t think that Gov. Romney is somehow responsible for the death of the woman who is portrayed in that ad,” Obama said. "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.”