The only local runoff in the Charleston region Tuesday settled the Republican race for House District 110 covering parts of downtown Charleston and Mount Pleasant.
Incumbent state Rep. William Cogswell Jr. successfully turned back a repeat challenge from Russell Guerard, who was making his third bid for the seat.
"And the last," Guerard said after conceding.
With all precincts reporting, Cogswell held a 59 percent to 41 percent lead, a difference of about 660 votes.
Cogswell faces Democrat Ben Pogue in November.
Cogswell, a freshman lawmaker, was among a group of two dozen legislators who earlier this year made a pitch to re-write the state's constitution.
Their issue was that the current system gives too much authority to the Legislature and too little to the governor, allowing a handful of influential legislators to hold massive sway over the entire state. The idea stalled.
Conservation Voters of South Carolina issued a statement Tuesday saying it was "instrumental" in the win. The group said it invested more than $20,931 in the primary and runoff, sending 47,366 pieces of mail and knocking on over 10,137 doors on Cogswell's behalf.