By Harriet McLeod
CHARLESTON, S.C., March 16 (Reuters) - A comedian's sister and a philandering ex-governor lead a field of 18 candidates seeking to fill a vacant U.S. congressional seat in Tuesday's special election, reminding voters how "Appalachian Trial" became a euphemism for extramarital affair.
Coastal South Carolina's 1st Congressional District needs to fill the vacancy left by Tim Scott, who was appointed to replace Jim DeMint in the U.S. Senate after DeMint resigned to head the Heritage Foundation, a conservative think tank.
Sixteen Republicans will compete in Tuesday's primary, including former Governor Mark Sanford, who once secretly left the country to visit his Argentine mistress, and the son of media mogul Ted Turner.
Two Democrats are also running on Tuesday, including Elizabeth Colbert Busch, sister of television comedian Stephen Colbert, who faces a perennial candidate in the Democratic primary and is expected to win in her first run for political office.
The general election is set for May 7.
"Typical of South Carolina, when there's truly an open seat, everybody and his brother seems to run for it because we have a habit of electing incumbents," said Kendra Stewart, associate professor of political science at the College of Charleston.
Sanford is looking to make a political comeback by way of the office he held from 1995 to 2001.
As governor in 2009, he tearfully admitted to an extramarital affair after he abruptly left the state for a week. He told aides he was hiking the Appalachian Trail, when in fact the married politician was visiting his girlfriend in Buenos Aires.
Sanford, 52, paid more than $70,000 in fines for ethics violations that included use of state funds to fly to Argentina. He divorced and served out of the rest of his term in disgrace.
"I've experienced how none of us go through life without mistakes," Sanford said in his first campaign ad. "But in their wake, we can learn a lot about grace, a God of second chances, and be the better for it."
SANFORD UNDER FIRE
Opponents have been quick to remind voters of his past transgressions and some also have questioned whether Sanford was as fiscally conservative as he says.
"Mark Sanford has huge name recognition, but so too does Lance Armstrong right now," said Republican opponent Robert "Teddy" Turner, a business owner turned high school economics teacher, the son of Ted Turner.
Teddy Turner, 49, who is seeking elected office for the first time, has tried to distance himself politically from his father, known as the "Mouth of the South" for his outspoken views, and his former stepmother Jane Fonda, who is still reviled among many conservatives for her Vietnam War protests.
"That's the 800-pound gorilla in the room. It's a little bit of a challenge to convince folks that you're conservative," said Turner, who has been a vocal critic of Democratic President Barack Obama's healthcare reform law, or Obamacare.
South Carolina's 1st Congressional District encompasses parts of coastal Charleston County and nearby rural counties and extends south along the coast to include wealthy Hilton Head Island.
The Republican candidates also include a number of state legislators, a former sheriff and a couple of engineers. No public polls have been conducted to show who has an edge.
Sixty percent of the Republican-leaning district voted for Mitt Romney in last year's presidential election and it hasn't elected a Democratic representative since 1981, said Alex Stroman, executive director of the state Republican Party.
But Stewart said Republicans could emerge from the primary bruised, giving Colbert Busch, the business development director for Clemson University's wind energy facility, a boost as the campaign moves toward the general election.
"Democrats have an ideal candidate to take this district if a Democrat could do it," Stewart said.
If no Republican gets more than 50 percent of the vote on Tuesday, the top two vote-getters will meet in a primary run-off on April 2. (Editing by Colleen Jenkins, Daniel Trotta and Andre Grenon)