Problem: What is the main difference between an incumbent race and an open election? An open election happens during a midterm year, whereas an incumbent race happens during a presidential election. A sitting president is pitted against a challenger in an incumbent race, while both candidates are new in an open election. An open election involves voters casting a non-secret ballot, whereas the ballot is kept secret during an incumbent race. In an incumbent race, only those who have voted before may vote, whereas anyone may cast a vote in an open election.