The criticism of Mitt Romney's time at Bain Capital didn't damage him dramatically in South Carolina, but it did have a small effect as Newt Gingrich won over a significant number of voters concerned about the economy, according to exit polls.

About two-thirds of voters viewed Romney's tenure at the private-equity firm positively, a benefit to the front-runner's effort to tie his private-sector background to his argument that he's the most competent candidate to deal with the economy. But 28 percent of voters saw his Bain history as negative, a figure that ABC News's Gary Langer, of Langer Research Associates, calls "not insubstantial."

Among that 28 percent, Romney won the support of only 3 percent, while Gingrich got 50 percent, the exit polls show.

Gingrich can also add some economic bona fides to his resume after tonight's vote. Among 79 percent of voters who said they were "very worried" about the economy, Gingrich won over 41 percent of them, while Romney got only 27 percent. (In New Hampshire, Romney was the one who had 41 percent support in that group.)

"Romney may look to a variety of misplays," Langer notes. "His hesitating position on release of his tax returns may have played a role in damaging his image of electability. It also may have hurt views of his leadership more broadly, and economic leadership by extension; among the broad majority of voters who cited the economy as the most important issue, Gingrich beat Romney by 40-32 percent - narrower than Gingrich's margin overall, but a win in a group that Romney owned in New Hampshire and Iowa alike."