Senator Lindsey Graham of South Carolina holds a commanding lead over his primary challenger, Mark Lynch, in the latest Republican Senate primary poll. The survey results show Graham leading across all demographic groups, a rare occurrence according to pollster Matt Towery from InsiderAdvantage.
A new InsiderAdvantage poll of likely Republican primary voters conducted May 13-14 shows Graham at 56 percent, Lynch at 13 percent, other candidates at 8 percent, and 23 percent with no opinion or undecided.
“Graham’s lead across every demographic is something unusual in polling,” Towery commented. “In our comprehensive survey, over 60% of respondents believe that President Trump’s endorsement of Graham will secure his victory. Graham’s main task now is ensuring voter turnout.”
President Trump reaffirmed his support for Graham in April, disparaging Lynch in a post on Truth Social. Trump praised Graham’s performance as “fantastic” and labeled Lynch as a “LUNATIC” who backs Representative Thomas Massie of Kentucky, whom Trump criticized as “perhaps the Worst Congressman in the History of our Country.” Trump warned that Lynch would be “a DISASTER for the Republican Party,” while Graham “GETS THE JOB DONE,” encouraging voters to support Graham wholeheartedly.
In May 2025, Lynch appeared on News Saturday, arguing that Americans are “tired of Lindsey and the fake platform he runs on.” Lynch claimed that although “Trump needs some things out of Lindsey,” Graham “still resists Trump and fights him at every turn.” He added, “We love President Trump, but that endorsement won’t save him this time.”
A March poll, conducted exclusively for Lynch’s campaign using Pulse Opinion Research’s methodology with Rasmussen Reports, initially showed Graham leading Lynch 41% to 21%, with Paul Dans at 11% and 22% undecided. However, after respondents received more information about the candidates’ records, Lynch edged ahead with 34% compared to Graham’s 23%, while Dans stayed at 11% and 26% remained unsure.
“I’ve polled many races in the ’26 cycle, and Lindsey Graham stands out as one of the weakest incumbents,” remarked Mark Mitchell of Rasmussen Reports. “Despite his name recognition, Mark Lynch takes a clear lead on the informed ballot, presenting a significant opportunity.”
