AP Decision Notes: What to expect in South Carolina’s special U.S. Senate primary runoff

WASHINGTON (AP) — South Carolina Republicans will return to the polls Tuesday for the fourth time since June to replace the late U.S. Sen. Lindsey Graham on the fall general election ballot.

Graham won the June 9 Republican primary for renomination to the seat he first won in 2002, but his unexpected death on July 11 from an aortic tear created a vacancy not only for his current U.S. Senate seat but also as the party’s pick to compete for another six-year term.

The finalists for the Republican nomination are Graham’s sister, U.S. Sen. Darline Graham , who was appointed to serve out the remainder of her brother’s current term, and U.S. Rep. Ralph Norman , a five-term congressman who ran for governor earlier in the year and placed third in the primary.

Darline Graham placed first in the Aug. 11 special primary but fell shy of the vote majority needed to avoid Tuesday’s runoff. She received about 33% of the vote, compared to about 25% for Norman. U.S. Rep. Russell Fry placed third with about 20% of the vote.

Graham swept the counties across central South Carolina, including the Columbia area, as well as the state’s Low Country region, which includes Charleston. She scored her highest percentages in counties along the Georgia border.

Norman performed best in the state’s Piedmont and Upcountry regions, including the Greenville area. Fry did best in the eight counties in the Pee Dee and Waccamaw regions that he represents in Congress.

Fry endorsed Graham after he lost the primary. She also has key backing from Republican U.S. Sen. Tim Scott and President Donald Trump , who was an early proponent of Graham and held a campaign rally with her Friday in Myrtle Beach.

Greenville County is the most populous in the state and typically contributes the most votes in statewide Republican primaries. It also has bucked against the front-runners in recent Republican primaries. Norman also carried Greenville County in the gubernatorial primary, and it was one of the only counties Lindsey Graham lost in his final election.

Democratic-leaning Richland and Charleston counties have the next-largest populations and contribute a sizable number of votes in Republican primaries, but they tend to be more influential in Democratic contests.

Horry, Lexington and Spartanburg counties are also large counties that have big impacts on Republican primaries. Spartanburg was the only other county Lindsey Graham lost in the June primary.

The winner will face Democratic nominee Annie Andrews , a Charleston pediatrician who challenged Republican U.S. Rep. Nancy Mace in the 1st Congressional District in 2022.

Lindsey Graham last won reelection in 2020 with 54% of the vote. Trump carried the state in 2024 with 58% of the vote.

Here are some of the key facts about the election and data points the AP Decision Team will monitor as the votes are tallied:

Polls close at 7 p.m. ET.

The Associated Press will provide vote results and declare a winner in the special Republican primary runoff for U.S. Senate.

Voters who participated in the Democratic primary on June 9 may not participate in the special Republican primary runoff on August 25. Only Republican primary voters or registered voters who did not participate in any party’s primary on June 9 may cast ballots in Tuesday’s election.

As of Friday, there were about 3.4 million registered voters in South Carolina. Voters in South Carolina do not register by party.

About 465,000 voters cast ballots in the June 9 Republican U.S. Senate primary when Lindsey Graham was renominated. About 336,000 voters participated in the Aug. 11 special Republican U.S. Senate primary.

About 19% of the vote in Aug. 11 Republican special primary was cast early in-person or by mail.

As of Friday, about 45,000 ballots had already been cast in Tuesday’s election.

Nearly all of South Carolina’s 46 counties release all or almost all of their early in-person and mail voting results in the first vote update of the night, usually before releasing any results from in-person Election Day voting.

In the Aug. 11 special primary, the AP first reported results at 7:13 p.m. ET, or 13 minutes after polls closed. The last vote update of the night was at 11:25 p.m. ET with more than 99% of total votes counted.

The AP does not make projections and will declare a winner only when it’s determined there is no scenario that would allow a trailing candidate to close the gap. If a race has not been called, the AP will continue to cover any newsworthy developments, such as candidate concessions or declarations of victory. In doing so, the AP will make clear that it has not yet declared a winner and explain why.

In South Carolina, recounts are automatic if the margin between the winning and losing candidates is 1% of the total vote or less. The AP may declare a winner in a race that is subject to a recount if it can determine the lead is too large for a recount or legal challenge to change the outcome.

As of Tuesday, there will be 70 days until the 2026 midterm elections.

Follow the AP’s coverage of the 2026 election at https://apnews.com/projects/elections-2026/ .