Trump Endorsed Lindsey Graham's Sister. She Still Has to Beat Ralph Norman in a Runoff on August 25.

Sen. Darline Graham and Rep. Ralph Norman advanced to a runoff Tuesday in South Carolina's Republican special primary for the Senate seat her brother held for four terms, after neither cleared the 50% threshold that state law requires to win outright. The runoff is set for August 25.

The seat became vacant on July 11, when Sen. Lindsey Graham died suddenly at 71. Gov. Henry McMaster appointed Darline Graham to serve out the remainder of the term. The appointment solved one problem and created another: Lindsey Graham had already won the Republican nomination in June for a full six-year term, so his death left the party without a candidate on the November ballot and forced Tuesday's special primary to pick one.

Darline Graham, 62, spent her career in disability services and served as commissioner of the South Carolina Commission for the Blind. She had never run for office. Days after being sworn in, she announced she would seek the full term, and President Trump encouraged the run and endorsed her.

The endorsement did not clear the field. Ten Republicans filed, including Norman, former Gov. Mark Sanford, Rep. Russell Fry, who has served in the House since 2023, and businessman Mark Lynch, who lost the June primary to Lindsey Graham. Norman, a hard-line conservative who has spent much of his House career at odds with Lindsey Graham's brand of institutional Republicanism, forced the runoff by consolidating the part of the primary electorate that never liked the seat's previous occupant.

That is the fault line the next two weeks will be fought along. Graham is running as the continuation of her brother's seat and as the president's choice. Norman is running as the argument that Trump's endorsement of a first-time candidate is not a sufficient reason to hand her six years in the Senate. In a runoff, where turnout collapses to the most committed voters, the second argument travels further than it does in a ten-way field.

Whoever wins on August 25 is heavily favored in November. Lindsey Graham won reelection in 2020 with 54% of the vote, and Trump carried South Carolina with 58% in 2024. Democrats have not won a Senate race in the state since Fritz Hollings in 1998. The practical effect is that the runoff, not the general election, decides who fills one of the Senate's 100 seats — and it decides it in a contest that will be settled by a fraction of the state's Republican voters two weeks from now, in the last full week of August.