At a news conference following the close of the NATO summit in Chicago, Obama was asked whether he supported commercials developed by his campaign staff faulting Romney for job losses while he was at Bain Capital, which would buy firms, sell off their assets and shut them down.
Obama said Romney's role at Bain is relevant to the campaign.
"The reason this is relevant … is my opponent, Gov. Romney, his main calling card for why he should president is his business experience," Obama said. "He's not going out touting his experience in Massachusetts. He's saying, 'I'm a business guy, I know how to fix it, and this is his business.'"
Obama said unlike Romney's role at Bain, the role of president is quite different.
"Your job is not to simply maximize profits. Your job is to make sure everyone has a fair shot," Obama said.
Cory Booker, the mayor of Newark, N.J., Sunday criticized the ads as "nauseating."