Comedy Central's Stephen Colbert waded once more into the congressional race in South Carolina pitting older sister Elizabeth Colbert Busch against former governor Mark Sanford Wednesday, taking aim at the way MSNBC's "Morning Joe" covered Sanford and touting his sister's credentials.

Colbert, speaking in character on "The Colber Report" as a faux-conservative commentator, said he wasn't planning to talk about the campaign on his show, but decided to after watching coverage of Sanford on "Morning Joe."

"This morning was just pure infomercial for his buddy, Mark Sanford," said Colbert of "Morning Joe" co-host Joe Scarborough, a former Republican congressman who called himself a "good friend" of Sanford's.

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Colbert then played clips of Scarborough praising Sanford on the show.

Sanford appeared on "Morning Joe" Wednesday morning after winning the GOP runoff in South Carolina's 1st district on Tuesday, advancing to a May showdown against Colbert Busch. "Morning Joe" co-host Mika Brzezinski said the program would also invite Colbert Busch to appear on the program.

"She's got her own show," quipped Scarborough. He added: "It's going to be 'Morning Joe' versus 'Colbert Report.'"

During the segment, Brzezinski alluded to Sanford's 2009 disappearance from South Carolina as governor and subsequent admission to an extramarital affair. "You're going to get it, on a number of levels on the personal side of this, so my question is why did you choose to put yourself through this," she asked him. Colbert did not play that clip on his show.

"After bring unfaithful to his wife and betraying the public trust, he gets a second chance in politics. Only in America -- and Italy," said Colbert, of Sanford.

Colbert concluded the segment by touting his sister's campaign, something he has done on his program before.

"Yes, she's a Democrat," said Colbert. "But she's a businesswoman, a job creator, who when raising three children on $14,000 a year went back to school, built a 20-year career in international trade and is now leading Mark Sanford in two consecutive polls."

Colbert will appear at two fundraisers for Colbert Busch this month.

The special general election will be held on May 7. Here's a closer look at how Colbert Busch and Sanford stack up against one another.