On the GOP ticket, he's facing off against Erika Harold and Michael Firsching. Harold is a former Miss America and lawyer in Champaign. Firsching is from Western Illinois. He's a veterinarian and a constitution expert.
Three others are on the Democratic side; Ann Callis, George Gollin and David Green. Callis is a former judge based in Madison County. Gollin and Green both work at UI. Gollin is a physics professor and Green works at the Institute of Government and Public Affairs.
Whoever wins Tuesday's primary has a long road to November. In 2012, Davis won the election, but only by about 1,000 votes. So, this is definitely a race to watch.
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