COLUMBIA — In a South Carolina primary season in which dozens of candidates have been disappointed by being tossed off the ballot, two politicians have a chance to win more than one office in a state where simultaneous campaigns are allowed.

Freshman Rep. Tom Corbin, R-Travelers Rest, is among 100 legislative incumbents with no opponent from either major party, in a year when all 170 House and Senate seats are up for grabs. While Corbin’s virtually guaranteed a second House term, he’s also running for an open Senate seat in northern Greenville County, where he faces two primary opponents.

Meanwhile, Rep. Ted Vick, D-Chesterfield, is seeking a fifth term to his state House seat as well as running for the Democratic nomination in the crowded race for Congress in the state’s new 7th Congressional District, which runs through the Pee Dee and along the Grand Strand.

Candidates in South Carolina can seek more than one office in the same election.

“There is no prohibition in the law and it doesn’t say anything about running for multiple offices at once,” said Chris Whitmire, a spokesman for the South Carolina Election Commission. “If a candidate does everything they need to do to get on the ballot for one office and they do it for another, there is nothing in the law that stops them.”

But if a candidate does win both seats, the law prevents dual office holding. A candidate who wins two must select the position he or she wants. If the other is a state House or Senate seat, then the voters have to return to the polls in a special election to fill the vacated one.

And that costs the taxpayers. The average cost for a special election for a state House seat is $20,000 while for a state Senate seat it costs about $35,000, according to the commission.

Corbin, a 47-year-old businessman, said he couldn’t pass up the opportunity to run for Senate after freshman Sen. Phillip Shoopman, who previously served a term in the House, unexpectedly withdrew April 15, citing personal reasons. Shoopman’s decision came more than two weeks after the normal filing period ended, causing the state GOP to reopen the race.

Corbin said Shoopman called him before withdrawing and encouraged him to run. After some prayer, as well as consulting with the House clerk and the state GOP on the legality, he went for it. But it was too late to withdraw from the House race, he said.

“I thought he was kidding,” Corbin said about the call. “This happened so unexpectedly and quickly — doors open up in life — I looked around and decided this is something I needed to do.”

Vick, a 39-year-old major in the Army National Guard, faces both a Democratic primary challenger and a Republican opponent for his state seat. He’s in a five-way primary race for the congressional seat. The Democratic nominee will run against the winner of a nine-way GOP primary. Vick referred questions on the double-filing to his campaign manager.

“He wanted to make sure he’ll be able to continue serving,” Lachlan McIntosh said. “Service is his life. It gives voters the opportunity to allow that.”

The South Carolina primary ballot has been whittled down following a state Supreme Court ruling earlier this month on improperly filed financial forms. The justices ruled that state law requires those seeking office to file their economic interest forms at the same time they filed for their candidacy.

The decision meant 87 Republicans and 95 Democrats in races statewide were invalidated, including 55 seeking state House or Senate seats. Before the court ruling, 80 incumbents faced no opposition.

For more than 20 years, state law has required candidates to turn in the economic interest form, intended to show voters any potential conflicts of interests, when they file their candidacy. There was confusion over when and how the statements needed to be filed because of a 2010 state law requiring online filing.

If not for the court ruling, there would have been another candidate seeking more than one office.

Republican Dick Withington of Georgetown County had filed to run for both a state House and state Senate seat as well as the 7th Congressional District seat. He remains on the ballot only as a congressional candidate.

Whitmire says candidates often run for more than one seat at a time.

“From our perspective, and we’re dealing with all these state level offices, it’s not uncommon,” Whitmire said. “More often than not it’s somebody in a lower office and they are trying to seek a higher office and they sort of hedge their bets by running for both.”

Associated Press correspondent Bruce Smith in Charleston contributed to this story.