Incumbent Senator Lindsey Graham leads Polymarket odds at 81% in the South Carolina Republican Senate primary on June 9, reflecting trader consensus on his enduring name recognition, fundraising edge, and fresh endorsement from Donald Trump on April 10, which praised his policy alignment while criticizing challenger Mark Lynch. A March Pulse Opinion Research poll of likely GOP voters showed Graham at 41%, Lynch at 21%, and Paul Dans at 11%—with 22% undecided—signaling runoff risk under South Carolina's top-two system if no candidate exceeds 50%. Dans's exit the same day and endorsement of Lynch as the "America First" alternative boosted the Greenville businessman's share to 13.6%, though traders discount polls amid Graham's historical primary dominance. Thomas Murphy trails at 0.2% with minimal traction.