While the Obama campaign continues its assault on Mitt Romney for his refusal to release more tax returns and his time at Bain Capital, could it run the risk of hurting President Obama's brand?

The Obama campaign has noted that polls show that highlighting Romney's time at the private equity firm has worked. Last month, an NBC/Wall Street Journal poll found that 33% of swing-state voters saw Romney's business experience negatively while 18% viewed it as an asset.

And some conservative commentators and Republican politicians, including Rep. Ron Paul and former Republican National Committee chairman Michael Steele, in recent days have warned that Romney needs to release more of his tax returns or risk being dogged by the issue.

Conservative commentators William Kristol and George Will even backed the Team Obama argument that Romney's unwillingness suggests that he has something to hide.

But for Obama, who ran on a message of "Hope and Change" in 2008, is there the risk of going too negative and turning off voters?

It's a question that NBC Today show host Matt Lauer pressed Obama's deputy campaign manager, Stephanie Cutter, on this morning.

"I think the president is laying out the choice," Cutter told Lauer. "Elections are about choices. And we have two very different directions that we can go in this country and that's what the president is communicating."

In more recent days, Team Obama has stepped up the pressure on Romney to release a dozen years of tax returns as his father, former Michigan governor George Romney, did when he ran for the GOP nomination in 1964.

With several news reports questioning whether Romney did indeed leave Bain to run the Salt Lake City Olympics in 1999 as he's repeatedly insisted, the Obama campaign has argued that it's even more important that Romney release more tax returns to shed light on his financial interests during that period.

That period is crucial because several Bain Capital investments made during that time were in companies that moved jobs overseas. The Obama camp has used Romney's tenure at Bain to make its case that he would outsource U.S. jobs.

The Obama campaign dialed up the rhetoric on the tax records with a new ad it is airing today in the Pittsburgh market where Romney is campaigning. The ad concludes with this sharp question, "What is Mitt Romney hiding?"

Lauer reminded Cutter that in accepting the party's nomination at the Democratic National Convention in 2008, the president said, "If you don't have a record to run on then you paint your opponent as someone people should run from."

Cutter shrugged off the implication of Lauer's question that Obama doesn't want to talk about his record. She added that Romney's business dealings are central to what he contends qualifies him to be president.

"Matt, I think that in talking about Mitt Romney's record -- we're happy to talk about the president's record," Cutter told Lauer. "The president is out there every single day doing that."

USA Today