Ron Paul is facing new questions on the campaign trail about inflammatory newsletters dating back to the 1980s, as the outsider Republican candidate gains steam in Iowa just days before the caucuses.
The newsletters from the 1980s and 1990s, under names like Ron Paul's Freedom Report and the Ron Paul Investment Letter, contained several instances of racially charged language and other offensive statements. While the newsletters have attracted renewed scrutiny in the media over the last few days, Newt Gingrich piled on Friday, saying the missives raise "fundamental questions" about the libertarian-leaning Texas congressman.
"These things are really nasty, and he didn't know about it? Wasn't aware of it?" Gingrich said at a stop in South Carolina.
Paul has since denied writing, and in some cases even reading, some of the newsletters that bore his name. But the issue could continue to haunt him as he rides a wave of support in Iowa at just the right time.
A line from one of the newsletters referring to the 1992 riots in Los Angeles said: "Order was only restored in L.A. when it came time for the blacks to pick up their welfare checks."
Reuters this week also reported on an ad for the newsletters from the early '90s that discussed "the coming race war in our big cities" and the "federal-homosexual cover-up on AIDS" -- all under Paul's name.
Paul told Fox News on Friday that if he's guilty of anything, it's negligence.
"I think the charge, which could be a correct charge, is I was pretty negligent as a publisher of a newsletter, not paying more attention," Paul said, adding: "I think that if someone thinks I'm perfect, then they are going to be disappointed."
But he said any attempt to portray him as racist would be "ironic," because as a civil libertarian he "champions civil liberties, regardless of race, creed, or color."
"The judicial system is very unfair to minorities. Nobody else would dare touch that," Paul said.
Paul said the controversial passages in those newsletters represented "probably one-hundredth of 1 percent or even less of all the thousands and thousands of pages."
He said they were mostly about financial and economic issues.
Paul's explanation has attracted skepticism from Gingrich and others.
"Now Ron Paul wants us to believe he didn't know anything about these newsletters even though he was profiting from them?" questioned Rich Lowry, editor of the National Review.
Paul's well-known positions on foreign policy and other issues are also attracting new scrutiny.
After Rep. Michele Bachmann, R-Minn., got in a tense dispute with Paul at the most recent presidential primary debate over his foreign policy views, Gingrich on Saturday assailed Paul's "isolationist" policies.
"The only person I know who's for a weaker military than Barack Obama is Ron Paul," Gingrich said. "His positions are fundamentally wrong on national security."
Paul wants to dramatically shrink the U.S. military presence around the world and has rejected as war propaganda warnings about the Iranian nuclear program.
"Should he be locked up in prison or should we see him as a political hero? Maybe he is a true patriot -- who reveals what's going on in government," Paul said.
Analysts say most GOP contenders don't take Paul seriously enough to spend any of their campaign cash on ads highlighting his edgy positions, and that the statements actually work against him with the GOP base. For the time being, Paul's numbers are soaring in Iowa, where several recent polls have put him a few points ahead of Gingrich and former Massachusetts Gov. Mitt Romney.
But while it may be unlikely that Paul will be the GOP nominee, some experts believe he will have a significant impact on who ultimately is.
"My sense like the last time -- he stayed in the race all the way. He'll have delegates this time and he can play some kind of a role if the race is close," said Republican strategist Ed Rollins.
Fox News' Shannon Bream contributed to this report.