Election Day is only the opening act for Mississippi. Read more

A runoff is widely expected to be needed later this month to settle who will serve the rest of Thad Cochran’s Senate term: the appointed Republican successor, Cindy Hyde-Smith; Mike Espy, a Democratic former agriculture secretary; or the conservative firebrand Chris McDaniel, who tried and failed to unseat Mr. Cochran four years ago. Assuming no one captures a majority on Election Day, the top two candidates will advance to a final showdown on Nov. 27. (Mr. Cochran, who was ailing, retired in April; he had been in the Senate since 1978.)

The state’s other Senate seat, currently held by Roger Wicker, a Republican, is also on the ballot this year, as regularly scheduled. Mr. Wicker is heavily favored to win re-election. The race to succeed Gov. Phil Bryant, a Republican who cannot run again because of term limits, takes place in 2019.