Republicans in South Carolina and Oklahoma will decide their nominees in pivotal head-to-head runoffs Tuesday, with the winners expected to be overwhelming favorites in November. In South Carolina, Darline Graham, the sister of longtime incumbent Lindsey Graham, is seeking the Republican nomination for a full six-year Senate term after being appointed to fill the remainder of his term following his sudden death in mid-July. She led the Aug. 11 primary but fell short of the 50% needed to avoid a runoff against Rep. Ralph Norman. Kalshi’s prediction market gives Graham a 67% chance of winning, compared with 34% for Norman. President Trump has endorsed Graham, making the contest another test of his influence after recent losses by his preferred gubernatorial candidates. In Oklahoma, Trump-backed former Oklahoma Secretary of Budget Mike Mazzei faces Oklahoma Attorney General Gentner Drummond in a Republican gubernatorial runoff after the candidates each won just over a quarter of the first-round vote. The remaining primary calendar includes contested Democratic races in Massachusetts, New Hampshire and Rhode Island.