MYRTLE BEACH, S.C. — It’s a warning sign for Sen. Darline Graham when devoted fans of President Donald Trump, who are decked out in MAGA gear and wait hours in the summer heat to watch him speak, aren’t sold on giving her a six-year Senate term.

Trump rallied Friday evening with Graham, the South Carolina Republican who was appointed by the state’s governor to finish the term of her elder brother, Lindsey Graham, who died suddenly last month at 71.

She faces five-term Rep. Ralph Norman, R-S.C., in Tuesday’s runoff. The winner will be a heavy favorite this fall against Democratic nominee Dr. Annie Andrews in this red state.

“I’m going to vote for Ralph Norman, unfortunately for Graham,” said Daniel Musick, a Myrtle Beach voter who called Trump “the best president we’ve ever had.”

“It’s just that she’s untested. I don’t know enough about her,” he said.

Graham’s candidacy has come under scrutiny after a couple of high-profile blunders at Tuesday’s GOP debate. When asked if Taiwan and the South China Sea are U.S. national security issues, she said she’s “not that informed on national security.” She also said that are “50 million people in South Carolina” — the state’s population is just under 5.6 million.

The debate was enough to move Musick, who said Graham’s answer on China and Taiwan made it “really unclear that she knew her foreign policy.”

“To me, that was the biggest issue,” Musick said, contrasting Graham with Norman, whose views he said align with his own.

Others were also weighing the debate as they arrived to hear Trump speak. Glenda Clinkscales, who lives near Anderson, said Graham had “some good answers and some not-so-good answers” and that the performance would factor into her vote.

Still undecided, Clinkscales said she wanted to hear more from Graham on Friday night before making up her mind.

Roger, a Myrtle Beach voter who wore a black “DARK MAGA” T-shirt and asked that his last name not be published, said Trump’s endorsement carries some “weight” with him — but he remained undecided.

He appeared unimpressed by Graham’s debate performance.

“Her people should have briefed her a little bit more,” he said. “Foreign policy is something that — you’re going to come in as a new senator, as a rookie, you’re gonna have to learn that.”

He added that he wants to look more closely at Norman’s policies before deciding who he’ll vote for on Tuesday.

The contest marks another test of Trump’s endorsement power after he quickly endorsed the younger Graham for the seat. While his support remains highly coveted by GOP candidates, Trump has had some significant misses in primaries this year.

“I asked her to do this,” Trump told the crowd. “She only knows how to put America first. She will be somebody you’re going to be very proud. You vote for her, you’re going to be very proud of that vote … We need every South Carolina patriot to go to the polls and vote for Darline Graham, if you would.”

There’s no doubt that Republican primary candidates would prefer to have the president’s endorsement than not. And indeed, for some voters outside the rally, Trump’s backing was all they needed to commit to voting for Graham.

“Honestly, I don’t know as much about the platforms there, but if Trump supports her, I do too,” said Republican voter Lynn Spivey.

Don Fulcher similarly said he’s voting for Graham “because Trump’s endorsing her.” He said Trump’s endorsement matters “a lot, because she’s going to support him also.”

Some in the party wonder why Trump is expending political capital for Graham in a state where the GOP is heavily favored this fall regardless of who wins the primary.

The initial primary results showed warning signs for Graham. Despite Trump’s endorsement, she secured just 33% of the vote in a crowded field.

“Don’t be surprised if Norman wins,” said a GOP strategist, who requested anonymity to speak candidly. “Trump coming to South Carolina puts him even more out on a limb for her. He’s had a bunch of endorsements fail to get folks over the finish line, but this would be a big one. But if he can muscle her into this seat, it’s a big victory for him.”

Also speaking at the rally Friday was Rep. Russell Fry, whose district includes Myrtle Beach and who finished third in the initial primary, with nearly 20% of the vote. He has since endorsed Graham, and his voters could prove important.

Norman, a member of the hard-right House Freedom Caucus, has argued that Graham is not prepared for the job while stressing his continued support for Trump and his agenda. He finished second to Graham in the Aug. 11 primary, forcing Tuesday’s runoff after no candidate received a majority.

Graham sought to turn Norman’s tenure around on him Friday.

“I’ve done more in 20 days than Ralph Norman has done in 20 years,” she said at the rally, while promising to be more supportive of Trump’s agenda than Norman has been. “We already have enough problem Democrats. We don’t need a problem Republican.”

Like others in the Freedom Caucus, Norman has occasionally tussled with the White House by trying to steer Trump’s agenda to the right. Norman also backed former South Carolina Gov. Nikki Haley over Trump in the 2024 presidential primary. But he has continued to emphasize his support for the president and his agenda during the Senate race.

Mark Sanford, a former South Carolina congressman and governor, finished fourth in the primary. He endorsed Norman on Friday, saying he “holds the best shot at holding the line” on spending and deficits, citing the $40 trillion national debt.

He added that “the stakes are simply too high as our nation really is at a financial tipping point.”

Ahead of the rally, Trump weighed in on Graham’s debate moment, calling her “very smart” and said “she was being honest” about her knowledge.

“I mean, she’s going to do what the military wants, and really what the president wants,” Trump told reporters. “She understands that national security is my thing, and she is a terrific woman who answered.”