A runoff primary is a second primary election held in some states to determine which of the top two vote getters in the first primary will be awarded the party nomination for an office. Typically, if no candidate receives a majority of the vote in the primary election, there is a subsequent runoff election between the top two vote getters to determine the party candidate.
States with runoff primary provisions
Eleven states have provisions for primary runoff elections: Alabama, Arkansas, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, South Dakota, Texas and Vermont. Vermont holds runoffs only in the event of a tie. South Dakota only holds runoffs for the offices of U.S. Senator, U.S. Representative and the governor.