In recent years, Pennsylvania primary elections have attracted many candidates, often splitting the vote narrowly and allowing one candidate to win with support from only a fraction of voters.
To ensure that candidates that win their primary election are supported by a majority of primary voters, ten other states have implemented a primary election runoff system where if no candidate receives at least 50% of the vote in a primary election, then a second (or “runoff”) election is held between the top two candidates. The candidate with the most votes in the runoff election would be declared the winner.