Strategic Voting in Open Primaries

Abstract

The purpose of an open primary is to incorporate more moderate votes into the primary elections. This intention may backfire when nonparty members strategically participate in the primary: The result on an open primary might become even more extreme than when nonparty members are not allowed to vote. Realizing this, the party members might also vote strategically to counter-react. If this occurs, then it might actually coordinate the votes of the party's supporters. The effect of strategic voting behavior on the result of primary depends on the size of the party, turnout rate of the nonparty members, the positions of the candidates and the proportion of voters who vote strategically. Strategic voting behavior can sometimes improve social welfare.