Key facts
- President Donald Trump will rally in South Carolina on Thursday.
- The South Carolina Senate race between Republican Darline Graham and Democrat Annie Andrews is a toss-up.
- Republicans are concerned about contests in traditionally GOP-leaning states.
- Democrats are favored to win the House and Senate control is uncertain.
- Lindsey Graham, whose sister is running for the Senate seat, died in July.
President Donald Trump is scheduled to hold a campaign rally in South Carolina on Thursday, marking his second visit to the state in two weeks. This comes as new polls indicate a tight race for the Senate seat between incumbent Republican Darline Graham and Democratic challenger Annie Andrews. Republicans are increasingly concerned that South Carolina, a state that has historically favored the GOP, has become a competitive battleground in the upcoming midterm elections.