US Election 2012: Barack Obama defends Bain attacks on Mitt Romney "If your main argument for how to grow the economy is, 'I knew how to make a lot of money for investors,' then you're missing what this job is about," he added, taking aim at Mr Romney's argument that his business record makes him a better candidate to restore the economy. The Obama campaign has rolled out a series of ads designed to cast Mr Romney as a heartless millionaire, with one yesterday accusing the former businessman of forcing a stationary company into bankruptcy and "walking away with" $100 million in profits. But the coordinated attack strategy was dealt a blow by Corey Booker, the high-profile Democrat mayor of Newark, New Jersey, who said he found the negative campaigning by both sides "nauseating." "I'm not about to sit here and indict private equity," he said in an interview on Meet The Press. If you look at the totality of Bain Capital's record, they've done a lot to support businesses, to grow businesses. This kind of stuff is nauseating to me on both sides. It's nauseating to the American public," he added. Mr Booker's comments were gleefully seized upon by the Romney campaign and met with intense irritation by Mr Obama's aides. "In this particular instance, he was just wrong," said David Axelrod, the President's top political strategist. The mayor, who is best know for his intense use of Twitter and his habit of personally rushing to the aide of constituent, later rowed back on his comments in a Youtube post that some political observers compared to a hostage video. The Obama campaign denied that it had pressured Mr Booker into the public recanting. Earlier this month Steve Rattner, the man who led the President's bailout of the US auto industry, also criticised the attacks, saying it was "unfair" to claim that Bain had a responsibility to create jobs when its obligation was to investors. "It did it superbly, acting within the rules and acting very responsibly and was a leading firm," he said. The Romney camp also stepped up its rhetoric yesterday, saying the President "refuses to accept moral responsibility for his failed policies."