AP Decision Notes: What to expect in South Carolina’s special primary to replace Sen. Lindsey Graham

WASHINGTON (AP) — Ten Republicans will compete in a special primary election Tuesday to replace the late U.S. Sen. Lindsey Graham on South Carolina's general election ballot. The candidates running to replace him include two congressmen, a former governor and Graham’s sister , now a U.S. senator appointed to serve out the final months of his current term.

Lindsey 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 for his spot on the November ballot as the party’s pick to compete for another six-year term.

U.S. Sen. Darline Graham , who was appointed by Republican Gov. Henry McMaster to fill her brother’s vacant seat, has President Donald Trump’s endorsement to compete in the general election as the new Republican nominee. Among those challenging her in the special primary are U.S. Reps. Russell Fry and Ralph Norman, former Gov. Mark Sanford and business owner Mark Lynch, who ran against Lindsey Graham in the June 9 primary.

Norman recently sought the nomination for governor and placed third in the primary.

If no candidate receives a vote majority in the special primary, the top two vote-getters will advance to a special primary runoff on Aug. 25.

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

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

Greenville County is the most populous in the state and typically contributes the most votes in statewide Republican primaries. It also has a bit of an independent streak. In the June 9 primary, a plurality of Greenville County voters preferred Lynch over Lindsey Graham in the U.S. Senate race and Norman over the two candidates who would advance to the runoff for governor.

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 where Lynch outperformed Lindsey Graham in the June primary.

Besides Greenville County, Norman also was the top vote-getter in York County and three smaller neighboring counties, all in his 5th Congressional District, in the June gubernatorial primary.

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 winners in the special Republican primary for U.S. Senate.

Voters who participated in the Democratic primary on June 9 may not participate in the special Republican primary on Tuesday. Only Republican primary voters or registered voters who did not participate in any party’s primary 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 in which Lindsey Graham was renominated. About 319,000 voters participated in the June 23 Republican gubernatorial primary runoff.

About 29% of the vote in the June 9 Republican state primary was cast early in person or by mail.

As of Friday, about 42,000 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 June 9 primary election, the AP first reported results at 7:22 p.m. ET, or 22 minutes after polls closed. The last vote update of the night was at 12:19 a.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 84 days until the 2026 midterm elections.

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