(CNN) -- Call it a one, two punch.
Elizabeth Colbert Busch brought up former South Carolina's Gov. Mark Sanford's affair in their one and only debate Monday night in the race to fill a vacant congressional seat in the Palmetto State.
Hours later, an independent group supporting the Democratic candidate touted that they're going up with a TV commercial highlighting a Republican voter who says she can no longer trust Sanford because of the affair that ended his marriage and sidetracked his political career. Meanwhile, Sanford is touting the endorsement of a high profile Republican.
House Majority PAC announced Tuesday that their spot will run throughout South Carolina's 1st Congressional District through next Tuesday's special election.
"I used to be for Mark Sanford, but not any more. He skipped town to be with his mistress on Fathers Day. Sanford even asked his wife for permission to have the affair," said Mt. Pleasant, S.C. Republican voter Jennifer Stark, in the spot.
"He wasted our taxpayer dollars on himself. I really was disappointed when I heard the extent to which he betrayed our trust. I was mortified, angry, embarrassed, betrayed. I'm a Republican but Mark Sanford just doesn't share our values."
Joel Sawyer, Sanford campaign spokesman, responded Tuesday telling CNN: "This new ad is still more evidence that pro-Pelosi forces are heavily invested in getting another reliable vote for her agenda in Congress. We believe voters of the First District will see through attempts to buy this race on Nancy Pelosi's behalf," Sawyer said.
The ad is House Majority PAC's third to attack Sanford, who's been open about his affair on the campaign trail, making it the subject of his first campaign commercial, and who's seeking political redemption by seeking the House seat he held for three terms before running for governor.
In Monday night's tense debate, Colbert Busch, an official with Clemson University's wind turbine drive testing facility who's best known nationally as the sister of satirist and Comedy Central host Stephen Colbert, took a swipe at Sanford over his secret 2009 trip to see his mistress in Argentina.
"When we talk about fiscal spending and we talk about protecting the taxpayers, it doesn't mean you take that money we saved and leave the country for a personal purpose," she said sternly, looking directly at her opponent on stage.
Her supporters in the crowd burst into applause and cheers. When one of the moderators motioned for Sanford to respond, an awkward exchanged ensued.
"I couldn't hear what she said," Sanford said, as Colbert Busch and some in the crowd began to laugh. "Repeat it. I didn't hear. I'm sorry."
"Answer the question," she replied.
"What was the question?" Sanford said, smiling. He went on to talk about the forced federal spending cuts known in Washington as the sequester.
Sanford was in his second term as governor in 2009 when he briefly disappeared from public view for several days. At the time his staff claimed he'd been hiking the Appalachian Trail. He later admitted that he was actually in Argentina, seeing the woman with whom he was having an affair. He's now engaged to that woman.
The episode sank any hopes Sanford had of making a bid for the 2012 GOP presidential nomination. Sanford and then-wife Jenny were divorced in 2010 and he finished his second term as governor in January 2011, exiting to what many thought would be political obscurity.
But he's back, beating out 15 other candidates last month to win the Republican nomination in a congressional district that the GOP has held for over 30 years. And even with all his political baggage, he was considered the favorite in the May election until three weeks ago, when court documents revealed his ex-wife had filed complaints against Sanford for trespassing on her property. He's scheduled for a court appearance two days after the election.
Not long after the story broke, the National Republican Congressional Committee announced it was pulling out of the race and national Democratic groups announced they were throwing more money into the contest.
In the debate, Sanford repeatedly brought up money that national Democratic groups have poured into the South Carolina race recently. As he's done in the last week on the campaign trail, Sanford said a vote for Colbert Busch would also be a vote for House Democratic Leader Nancy Pelosi. To make that point, Sanford debated a cardboard cutout of Pelosi last week.
"What it says is, whose voice do you carry when you go to Washington, D.C.?" he said Monday, pointing to the hundreds of thousands of dollars that national Democratic groups have spent on the race.
But Colbert Busch sought to distance herself from Washington.
"I want to be very clear, Mark, nobody tells me what to do, except the people in South Carolina's 1st District," she said. "I am a fiscally conservative, independent tough businesswoman."
Trying to make her case, she criticized the Affordable Care Act, President Obama's health care reform that was passed by Congressional Democrats in 2010 and upheld by the Supreme Court last year. Colbert Busch argued there are points in the bill that are "extremely problematic," saying it's expensive, slashes Medicare benefits and costs jobs. But then she went on to highlight multiple provisions in the law that she favors.
Sanford Tuesday announced the support of Sen. Rand Paul of Kentucky, a leading conservative voice in the Senate and a probable 2016 GOP presidential candidate. CNN Political Reporter Peter Hamby was first to report news of the endorsement Monday evening.
"Mark has proven during his time in office that watching out for taxpayers and holding the line on spending are his top priorities. What we absolutely cannot afford is someone like his opponent, who will be yet another vote for a return to the Pelosi speakership, for disastrous programs like Obamacare, and for more spending and debt. I am pleased to endorse Mark and stand with him in this race," said Paul, in a statement put out by the Sanford campaign.
The congressional seat became vacant when Rep. Tim Scott, who won re-election by 27 percentage points in last November's election, was named by GOP Gov. Nikki Haley to fill the Senate seat of Sen. Jim DeMint, who stepped down late last year to take over as the head of the conservative Heritage Foundation.