Electoral Thresholds as Coordination Devices

In this paper, we study one-person–one-vote parliamentary elections where voters care both about the winner of elections and about the composition of the parliament. Parties enter the parliament if and only if their vote share exceeds some predetermined threshold. We show that equilibria generically exist in which all parties obtain a non-degenerate vote-share and, perhaps more importantly, we show that the size of the electoral threshold acts as a coordination device, which crucially affects the win prospects of the Condorcet winner party. In particular, we argue that the win prospects of the Condorcet winner party decrease with the size of the entry threshold.