As the midterm elections approach, voters in three US states - South Carolina, Georgia, and Oklahoma - will cast their ballots in special and run-off elections on Tuesday. These contests are significant as they will determine who will appear on the November ballot, potentially shaping the political landscape of the upcoming midterms. In South Carolina, Republicans will return to the polls for a second time since June to select a candidate to replace the late Senator Lindsey Graham. The late senator, known for his hawkish stance in Congress, had been a strong ally of President Donald Trump. The race features Graham's sister, Senator Darline Graham, and Representative Ralph Norman, with Darline Graham leading in the August primary but falling short of the majority required to avoid a run-off. Meanwhile, Oklahoma Republicans are set to settle an expensive nomination fight for governor while Democrats choose a nominee for a US Senate seat. The gubernatorial race has major implications for November's election as Democrats haven't won the Oklahoma governorship in 20 years. In the US Senate race, nurse N’Kiyla Jasmine Thomas and lawyer and minister Jim Priest are vying for the Democratic nomination, with Priest holding a significant fundraising advantage. Georgia will hold a special election to fill a vacant United States congressional seat following the death of a lawmaker. The winner will face Democratic nominee Annie Andrews in November. Additionally, Oklahoma voters will decide on two statewide ballot measures, including one that would add a voter identification requirement to the state constitution. This election season is set to test Trump's endorsement power and could have far-reaching implications for the midterm elections.