Regenwetter and Grofman [17] offer a probabilistic generalization of Sen's [25, 27] classic value restriction condition when individual preferences are linear orders. They provide necessary and sufficient conditions for transitive majority preferences on linear orders. They call these conditions...

The Laakso-Taagepera index (Laakso and Taagepera, 1979) has become the most commonly used measure to specify the ‘effective’number of political parties in a party system where parties vary substantially in their vote and/or seat shares. It is well known that the Laakso-Taagepera...

While there are many formal models that generate predictions about polarization, only a handful address the question of how, with no change in electoral rules, levels of polarization can dramatically vary over time, as they have in the US House during 150 years of two-party competition. We...

We develop and test predictions about the factors determining the competitiveness of elections to the U.S. Senate. To do so, we deliberately abstract away from candidate-specific conditions that have often been used to study political competitiveness in order to focus on basic structural...