Senator Darline Graham, appointed to complete the Senate term of her late brother, Lindsey Graham of South Carolina will face congressman Ralph Norman in a runoff election for the Republican nomination.

Graham held a narrow lead in the polls going into the abbreviated special primary on Tuesday, which predicted a close contest for second place. Norman, Russell Fry, a congressman, and Mark Sanford, a former governor, polled within a point of each other in the most recent survey from the Trafalgar Group.

The winner of the runoff on 25 August will face Annie Andrews, the Democratic nominee and a pediatrician, in November.

Graham has loudly trumpeted her endorsement from Donald Trump, but also enjoys the support of South Carolina’s governor, Henry McMaster, and John Thune, the Senate majority leader. In recent interviews the political outsider sought to convince people that her experience, and focus on affordability, made her the right candidate.

“I ran a state agency. I turned it from a struggling agency into a national model. I think that’s great experience to bring to the table,” Graham said, addressing reporters after casting her ballot on Tuesday. She highlighted the passage of a sanctions bill targeting Russia during her short tenure in Washington. “I was the deciding vote on Todd Blanche as attorney general. So I think I’ve accomplished a whole lot in three weeks.”

Norman’s congressional district in the suburbs of Charlotte is vote-rich for Republicans, contributing disproportionately to statewide primary results. Norman, who has served in Congress since 2017, also had broad support from state legislators and a statewide campaign apparatus that had largely remained intact after his failed primary bid for the governor’s office in June.

His campaign highlighted support for the Save America Act, a Trump-backed bill to impose federal requirements on states to mandate proof of citizenship at voter registration and to submit state voter rolls to federal oversight. He also has promoted a bill to strip housing funding from cities that do not cooperate with Immigration and Customs Enforcement (ICE).

The last-minute squabble for the Republican nomination saw a spectrum of conservative approaches to the seat, with candidates quickly turning on each other in debate, social media and political advertising.

Sanford, who served as governor between two stints in Congress, had campaigned on fiscal stewardship, noting the dramatic increase in the federal debt.

“I got into this race because I believe our nation is at a financial tipping point.” Sanford wrote on social media on Tuesday. “I held the line on spending as Governor unlike any Governor before or since and ask for your vote today so that I might fight for our grandkids’ ability to afford the American Dream.”

Fry’s political attack advertising amplified a comment Graham made in a debate that was favorable to datacenter development, and has likened her appointment to an act of “DEI” – the practice of diversity, equity and inclusion that has become anathema to the right.

Fry has come under fire from Graham and others for running simultaneously for the US Senate and to retain his congressional seat.

Statewide special elections in South Carolina are rare events. The resignation of Senator Jim DeMint, a Republican who left office in 2013 to lead the Heritage Foundation, triggered the most recent example. Governor Nikki Haley named then congressman Tim Scott as DeMint’s successor.

Scott won both the nomination and special election to complete the term handily, becoming only the second Black Republican senator since Reconstruction and the first Black senator in the southern United States elected directly by voters. He is now the longest-serving African American US senator in American history.