What to expect in the S.C. Republican presidential primary

WASHINGTON - Donald Trump and Nikki Haley will face off Saturday in South Carolina's first-in-the-South Republican presidential primary, the first head-to-head matchup for the last two remaining major candidates since the New Hampshire primary a month ago.

The contest takes place on Haley's home turf. She was South Carolina's governor for six years before stepping down in 2017 to serve as U.N. ambassador when Trump was elected president. Despite her history, Haley faces strong headwinds in a state where Trump has the support of most of the party establishment, has held a substantial lead in recent polls and enjoys high popularity among the conservative base.

Both candidates have made sharp attacks against the other, with Trump using derisive nicknames for Haley and playing down her work in his Cabinet. Haley has increasingly questioned Trump's fitness for office, most recently criticizing his comments on Russia and NATO. It is a marked contrast from earlier in the campaign when she and other GOP hopefuls avoided criticizing Trump directly.

The South Carolina primary is usually an indicator of which candidate will win the Republican presidential nomination. Since the modern version of the state's primary began in 1980, all but one GOP primary winner has gone on to win the party's nomination. The lone exception was Newt Gingrich in 2012.

A look at what to expect on election night:

PRIMARY DAY

The primary will be held Saturday, and polls will close statewide at 7 p.m.

WHAT'S ON THE BALLOT

The ballot will list Ryan Binkley, Chris Christie, Ron DeSantis, Haley, Vivek Ramaswamy, David Stuckenberg and Trump.

WHO GETS TO VOTE

South Carolina has an open primary system, which means any registered voter may participate in any party's primary. But voters may only participate in one party's presidential primary, so people who voted in the Democratic primary on Feb. 3 may not vote in the Republican contest.

Only about 4% of registered voters cast ballots in the Democratic contest, leaving the bulk of the electorate, including any Democrats and independents who favor Haley over Trump and didn't vote in the earlier contest, eligible to weigh in on the Republican race.

DELEGATE ALLOCATION RULES

There are 50 delegates at stake, and 29 will be awarded to the winner of the statewide vote. Twenty-one delegates will be allocated according to the vote in each of the state's seven congressional districts. The top vote-getter in each district will get three delegates from that district.

DECISION NOTES

The last time Haley won a competitive GOP primary in South Carolina was in 2010, when she was the top vote-getter in a four-way primary and was forced to a runoff, which she won handily. Six years later, Trump won a crowded six-way race in the state's presidential primary on his way to capturing the White House and becoming the dominant figure in Republican politics.

Republican electoral politics have changed dramatically since the last time Haley and Trump each faced other Republican candidates in the Palmetto State. Still, their past election results do provide some clues for Saturday's primary.

In their last competitive South Carolina primaries, Haley's strongest showings and some of Trump's worst were in counties where Democrats perform best in general elections.

Trump carried 44 of the state's 46 counties in the 2016 primary, all except Richland and Charleston, the second- and third-most populous. Haley won these counties by wide margins in her 2010 runoff, as did Democrat Joe Biden in the 2020 general election.

Haley's other strongest areas in 2010 were the relatively small counties of Bamberg, Lee, Marlboro and Orangeburg, all of which Biden carried, as well as Dorchester and Chesterfield, which Biden lost to Trump.

The results are broadly consistent with Haley's performances so far in the 2024 presidential primaries. Her strongest showings in Iowa and New Hampshire were in the states' Democratic-friendly areas, and her worst were in Republican-friendly areas.

These results suggest that Haley's best chance to win in South Carolina, or for a competitive result, would be to win big in the state's Democratic areas, especially in vote-rich Charleston and Richland, while staying competitive in the largest county of Greenville and minimizing the margins in heavily Republican areas. Likewise, she would likely need to perform well in votes cast before Election Day, which will be the first votes reported on election night in most counties.

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

WHAT DO TURNOUT AND ADVANCE VOTE LOOK LIKE?

There are about 3.3 million registered voters in South Carolina. Voters do not register by party. Turnout in the 2016 Republican primary was about 25% of registered voters. It was about 22% in the 2012 primary.

Saturday's contest will be the first Republican presidential primary held in the state since a new early voting law was enacted in May 2022. The law allows voters to cast ballots in-person before Election Day without an excuse.

The early voting period for the GOP primary is Feb. 12-22. In the 2016 Republican primary, when voters had to provide an excuse to cast an absentee ballot, about 8% of votes were cast before Election Day. In the 2022 midterm primaries, after the new law went into effect, pre-Election Day voting was at about 21%. About 36% of votes cast in the Feb. 3 Democratic primary were before Election Day.

As of Tuesday night, more than 139,000 voters had cast their ballots.

HOW LONG DOES VOTE-COUNTING USUALLY TAKE?

In the 2024 South Carolina Democratic primary, AP first reported results at 7:08 p.m.

Primary night tabulation ended at 10:47 p.m. with nearly 100% of votes counted.

ARE WE THERE YET?

As of Saturday, there will be 142 days until the Republican National Convention in Milwaukee and 255 until the November general election.