This Tuesday night, Republican voters in South Carolina will choose a nominee for the deep red state's 2026 U.S. Senate race. And the outcome, according to Politico, will be a crucial test for President Donald Trump's kingmaker skills, risking a "massive embarrassment."

Trump is campaigning for Sen. Darline Graham, appointed to the seat by GOP Gov. Henry McMaster after the death of her brother, the late Sen. Lindsey Graham (R-South Carolina). But a Graham victory is far from a given, and her primary opponent, Rep. Ralph Norman (R-SC), has plenty of supporters.

Politico reporters Alec Hernandez and Aaron Pellish explain, "Donald Trump is facing one of his biggest tests of the midterms — and it's of his own making. The president has spent a significant amount of time and money trying to help Sen. Darline Graham defeat Rep. Ralph Norman in Tuesday's snap GOP Senate primary. He's done more for Graham than he has for the battleground Republicans whose general election fights will determine control of Congress: Not only did he push her to run for a full term, he also held a rare in-person rally for her and tapped into his MAGA Inc. war chest during the final days of the race."

Hernandez and Pellish add, "If, after lending all that support, Graham fails, it would be Trump's most embarrassing loss of the cycle. A win, however, would let him flex his ability to power an unknown political figure to office."

GOP strategist Matthew Bartlett, who served in the State Department during the first Trump administration, stresses that the primary's importance goes way beyond Graham and Norman.

Bartlett told Politico, "If Darline does come up short, it would be just a massive, massive embarrassment to the White House and to the president. Just an utter rejection."

Another GOP strategist, Andrew Boucher — who chairs the Charleston County Republican Party in South Carolina — told Politico, "The fact that he came to the state on short notice to do a rally, and we haven't seen that in a lot of endorsements, I think that sends a very strong message that he's all in."

But a Republican operative, interviewed on condition of anonymity, argues that Graham "wouldn't even be in this place if she didn't have" Trump's support — adding, "The outside help she's had has kind of made this competitive."

Another GOP operative, also quoted anonymously, describes Sen. Tim Scott's (R-South Carolina) endorsement of Graham as a major advantage for her.

The operative told Politico, "Sen. Scott engaging in the race, the congressional delegation, all these portions of it. Congressman Fry engaging in the race is a big deal. You could almost say that's the opposite of what you had in the governor's race."

Reprinted with permission from AlterNet