The Influence of Party: Evidence from the State Legislatures

American legislative studies in recent years have been occupied to a large degree with the question of the effects of political parties on the policy behavior of elected legislators, with most of the research focusing on the U.S. Congress. We undertake a comparative analysis of state legislatures for a window into the character and extent of party's effects. Specifically, we compare the impact of party on the partisan polarization and dimensionality of campaign issue stances and roll call voting in the Kansas Senate and the largely comparable, though nonpartisan, Nebraska Unicameral. This comparison offers us a nice quasi-experiment to assess the impact of party by establishing a baseline condition in Nebraska for what happens when party is absent. We argue that party lends order to conflict, producing the ideological low-dimensional space that is a trademark of American politics. Where parties are not active in the legislature—Nebraska is our test case—the clear structure found in partisan politics disappears. This works to sever the connection between voters and their elected representatives and, with it, the likelihood of electoral accountability that is essential for the health of liberal democracy.