Spartanburg, S.C.--Searching for a lifeline to resurrect his flagging presidential campaign, Newt Gingrich struck a semi-populist tone here Wednesday, railing against “crony capitalism” and demanding that Mitt Romney be transparent about his days at Bain Capital.

Republican presidential candidate and former Speaker of the House Newt Gingrich speaks during a campaign event at the Laurel Creek Club on Wednesday in Rock Hill, South Carolina. (Mark Wilson/GETTY IMAGES)

“I think you miss the target on the way you’re addressing Romney’s weaknesses. I want to beg you to redirect and go after his obvious disingenuousness about his conservatism and lay off the corporatist vs. the free market,” said Dean Glossop, in an exchange first reported by POLITICO. “I think it’s nuanced,”

Gingrich, who spent the morning pushing back against criticism that he was mouthing liberal talking points, seemed to agree with Glossop.

“I agree with you. It’s an impossible theme to talk about with Obama in the background. Obama just makes it impossible to talk rationally in that area because he is so deeply into class warfare that automatically you get an echo effect,” Gingrich said. “As a Reagan Republican, in fact, it never occurred to me, until it happened, so I agree with you entirely.

“Romney’s record as CEO of Bain is fair game and it will be vetted in the view of the public,” said R.C. Hammond, a Gingrich spokesman. “Our recommendation is for him to hold a press conference as soon as possible to answer questions about why he did in certain business deals at Bain.”

Asked directly if he thought he crossed the line in criticizing Romney’s business background, Gingrich declined to comment.

In three campaign stops here, he argued that he was the true conservative and that voters should consolidate around him in order to stop Romney’s path to the nomination—his campaign sent out a letter echoing those sentiments earlier Wednesday.

“This is going to be a campaign for the next 10 days that is very specific about the need for a conservative, and why I believe a moderate can’t debate very effectively against Obama which I believe is the key to the election,” Gingrich said.

But on scrutinizing Romney’s record at Bain, which is the centerpiece of the frontrunner’s candidacy, Gingrich seemed to soften his tone a bit as the day wore on, perhaps owing the chorus of criticism.

In a morning speech, he talked about rooting out crony capitalism, big banks raking in the profits while small banks suffer, and called for “a free enterprise system that is honest. . . fair to everyone and gives everyone an equal opportunity to pursue happiness.”

By late afternoon, all of that language was striped from his campaign speech, suggesting that the former Georgia congressman is finding it hard to attack Romney’s years at Bain, without drawing the ire of other Republicans.

An aide said that Gingrich will continue to make an issue of Romney’s years at Bain.