Rivals of Republican frontrunner Mitt Romney have portrayed him as a vulture capitalist who indulged in buying out companies with little regard for the welfare of workers.

With Romney achieving impressive victories in Iowa and New Hampshire, his opponents, including former House Speaker Newt Gingrich and Texas Governor Rick Perry, have criticized the former Massachusetts governor's role at Bain Capital.

Bain Capital specialized in returning troubled companies to profitability. A major point of debate ahead of South Carolina's heated presidential primary is whether Mitt Romney created or destroyed jobs when he ran the private equity firm Bain Capital has become.

Private equity buyouts accelerate the process of creative destruction. Old jobs disappear more rapidly, new jobs get created more rapidly, and productivity growth increases as a result.

Romney has countered his critics by charging that they're attacking the free enterprise system. Romney supporters have argued that critics of his role at Bain Capital are really attacking capitalism itself. They argue that investment companies such as Bain assist economic growth by providing crucial seed money and expertise that allow troubled companies to get back to prospering conditions.

Raising a question of judgment about a particular person in a particular company who has made that one of his two major claims running for president is hardly an attack on capitalism, said Gingrich.

This is not venture capitalism. I think it's exploitative. I think it's not defensible, he said.

Venture capitalism is when you go in, you put in your money and you stick it out, Gingrich added.