Bostic, an underdog in the campaign, will face Sanford in an April 2 runoff election. The former governor, who fell from grace dramatically in 2009 after disappearing from the state and admitting to an extramarital affair, finished at the top of the 16-candidate GOP field on Tuesday, but failed to win a majority of the vote. That's why a runoff will decide the nomination.
The 1st district special election was triggered when Gov. Nikki Haley (R) appointed Republican Tim Scott -- the former representative of the 1st district -- to the Senate to replace Republican Jim DeMint, who resigned his seat earlier this year.
The winner of the Sanford-Bostic runoff will face Democrat Elizabeth Colbert Busch in the May 7 special general election. Colbert Busch is the sister of Comedy Central host Stephen Colbert.
The 1st district leans heavily Republican; Mitt Romney won nearly six in 10 votes there in 2012.