Some Democrats may not like it, but Obama’s allies argue that aggressive attacks on former Massachusetts governor Mitt Romney’s record at Bain Capital are working.

Priorities USA Action, a super PAC supporting President Obama, has released a polling memo finding that ads targeting Romney’s business record are having an impact in five key states.

Internal polling from Global Strategy Group and Garin-Hart-Yang Research Group in Colorado, Florida, Ohio, Pennsylvania, and Virginia suggests that Romney’s tenure at the private venture firm is more of a liability than an asset.

Thirty-seven percent of voters in those swing states are less likely to vote for Romney because of his work running Bain Capital, according to the memo. Twenty-seven percent say it makes them more likely to vote for him.

Fifty-eight percent of voters said Romney was in business to make money for himself and his investors, regardless of the impact on jobs or business.

“We’ve firmly established that Romney’s tenure was not about creating jobs,” pollster Geoff Garin told the Plum Line. “This sets the stage for what we’ll be doing later on.”

(Priorities USA Action)

Of course, this polling comes from a biased source. But a recent WSJ-NBC News survey also gave Obama an edge in battlegrounds pummeled with anti-Romney ads.

A Washington Post-ABC News poll released Tuesday found that voters are divided on Romney’s business past.

A bigger chunk of Americans thought as a corporate investor Romney did more to cut jobs than create them, 40 percent to 36 percent. Fifty percent said Romney’s corporate work was “not a major factor” in their vote. The other half was evenly split on whether it was a major reason to support (23 percent) or oppose (24 percent) Romney.

That suggests Obama and his allies still have work to do— but clearly, they are committed to this line of attack.

Since the beginning of May, Priorities has spent about $2 million in Colorado, $2.4 million in Florida, $2.3 million in Ohio, $1.6 million in Pennsylvania and $1.9 million in Virginia, according to a Republican media buyer.

Until recently, Romney largely ignored these attacks, many of which our Factchecker has deemed misleading. But according to BuzzFeed, the Republican’s campaign is planning to start calling out Obama as a “liar.” A recent Romney ad called Obama’s attacks “vicious lies.”

The Republican has some Democratic allies in rebutting these ads — former president Bill Clinton and Newark Mayor Cory Booker have both criticized the Bain campaign. But as much as people hate them, negative ads tend to be more effective than the complaints about them.