Republican presidential candidate Mitt Romney speaks during a campaign rally Tuesday in Florence, S.C. (Joe Raedle/GETTY IMAGES)

There’s a lot Mitt Romney wants voters to know about so-called super PACs.

Romney, who has benefited perhaps more than any other Republican presidential candidate from changes in campaign finance law allowing outside groups to spend unlimited sums on political advertising, told reporters here Tuesday that super PACs becoming larger than campaigns themselves is “a very bad idea.”

But, he noted: “It’s not that I don’t support super PACs. We raise money for super PACs. We encourage super PACs. Each candidate has done that.”

Romney said he believes that any political ad should be factually accurate – and that any super PAC associated with him should remove any inaccurate material from its ads. And Romney defended an ad by Restore Our Future, a pro-Romney super PAC, which attacks former senator Rick Santorum with what Santorum has called “dirty politics.”

“I hear that Rick Santorum is very animated that the Super PAC ad says that he is in favor of felons voting,” Romney said. “Well, he is! What’s he missing? That’s his position. He says, ‘Well, it makes it sound like they are people in prison.’ Well, actually, people who have been released from prison are still called felons if they have committed felonies.”

Although Romney professed familiarity with the anti-Santorum ad – as well as with another ad by Restore Our Future attacking former House speaker Newt Gingrich – he said he had not yet seen an ad by a super PAC supporting Comedy Central anchor Stephen Colbert. That ad, by the ironically titled “The Definitely Not Coordinating With Stephen Colbert Super PAC,” depicts Romney as a serial killer, labeling him “Mitt the Ripper.”

“Stephen Colbert is entitled to be a humorist and hopefully it’s funny,” Romney said. “Having not seen it, I don’t know whether I think it’s funny or not, but we’ll see.”

Romney invited a comparison to NBC’s “Saturday Night Live,” which has aired comedic routines making fun of Romney, including one skit last winter calling him “Willard Mitt ‘Danger’ Romney, J.D., M.B.A.”

“I’ve been watching the SNL skits, which I think have been very funny,” Romney said. Of Colbert, he added, “He has a tradition of being able to touch my funny bone.”