The first debate in the special GOP primary for the late Sen. Lindsey Graham's South Carolina Senate seat is set for Monday, offering nearly 10 candidates a chance to define themselves before voters. Political insiders say only a few are true contenders, including appointed Sen. Darline Graham, who has President Donald Trump's endorsement, along with Reps. Ralph Norman and Russell Fry, and former Gov. Mark Sanford. The debate is seen as a critical opportunity for candidates to prove they can handle the job, as campaign mailers and emails already flood voters' homes.