Disentangling the Role of Ideology and Partisanship in Legislative Voting: Evidence from Argentina

We present a novel approach to disentangle the effects of ideology, partisanship, and constituency pressures on roll‐call voting. First, we place voters and legislators on a common ideological space. Next, we use roll‐call data to identify the partisan influence on legislators' behavior. Finally, we use a structural equation model to account for these separate effects on legislative voting. We rely on public opinion data and a survey of Argentine legislators conducted in 2007–08. Our findings indicate that partisanship is the most important determinant of legislative voting, leaving little room for personal ideological position to affect legislators' behavior.     

Religion in the Legislative Arena: Affiliation,Salience, Advocacy,and Public Policymaking

Religion is a complex and multidimensional phenomenon that informs politics in various ways. This article examines the effects of religious affiliation, religious salience, and religious group advocacy on roll‐call voting in the Wisconsin state legislature. Various studies have demonstrated the impact of religious affiliation on legislative politics, but our use of additional religious indicators allows us to model the religious effect in a more accurate and nuanced manner. Using data from an original survey of state legislators, we utilized structural equation modeling to measure the direct and indirect effects of these religious factors on both the general pattern of roll‐call voting and voting on a high‐salience issue, abortion. Ultimately, the findings indicate that, even when we control for political party affiliation, which is a dominant influence on roll‐call voting, conservative Protestant religious affiliation and high religious salience influence legislative voting. We conclude with a discussion of the implications for future studies of religion in the legislative arena.     

Congressional Party Defection in American History

In this paper, we analyze the roll‐call voting behavior of House and Senate members who changed party affiliation during the course of their political careers. We analyze members who switched during the stable periods of the three major two‐party systems in American history: the Federalist‐Jeffersonian Republican system (3d to 12th Congresses), the Democratic‐Whig System (20th to 30th Congresses), and the Democratic‐Republican System (46th to 106th Congresses). Our primary findings are that the biggest changes in the roll‐call voting behavior of party defectors can be observed during periods of high ideological polarization and that party defections during the past 30 years are distinct from switches in other eras because of high polarization and the disappearance of a second dimension of ideological conflict.     

Legislative Voting Behavior,Seen and Unseen: A Theory of Roll‐Call Vote Selection

The empirical study of legislative behavior largely relies on roll‐call vote analysis, but roll‐call votes in many legislatures represent only a sample of legislative votes. We have good reasons to believe this sample is particularly poor for inferring party effects on legislative behavior. The selection of votes for roll call may be endogenous to exactly the characteristics of voting behavior (for instance, party cohesion) that we want to study. We must understand the roll‐call vote institution and account for its selection effects before we can draw inferences about legislative behavior from roll‐call results. This article develops a game‐theoretic model of roll‐call vote requests predicated on party leaders requesting votes to enforce party discipline. The model offers general and testable predictions about the selection process and how it affects observed and unobserved legislative voting behavior, particularly party cohesion.     

A Bridge to Somewhere: Mapping State and Congressional Ideology on a Cross‐institutional Common Space

Researchers face two major problems when applying ideal point estimation techniques to state legislatures. First, longitudinal roll‐call data are scarce. Second, even when such data exist, scaling ideal points within a single state is an inadequate approach. No comparisons can be made between these estimates and those for other state legislatures or for Congress. Our project provides a solution. We exploit a new comparative dataset of state legislative roll calls to generate ideal points for legislators. Taking advantage of the fact that state legislators sometimes go on to serve in Congress, we create a common ideological scale. Using these bridge actors, we estimate state legislative ideal points in congressional common space for 11 states. We present our results and illustrate how these scores can be used to address important topics in state and legislative politics.     

Comparing NOMINATE and IDEAL: Points of Difference and Monte Carlo Tests

Empirical models of spatial voting allow us to infer legislators' locations in an abstract policy or ideological space using their roll‐call votes. Over the past 25 years, these models have provided new insights about the U.S. Congress, and legislative behavior more generally. There are now a number of alternative models, estimators, and software packages that researchers can use to recover latent issue or ideological spaces from voting data. These different tools usually produce substantively similar estimates, but important differences also arise. We investigated the sources of observed differences between two leading methods, NOMINATE and IDEAL. Using data from the 1994 to 1997 Supreme Court and the 109th Senate, we determined that while some observed differences in the estimates produced by each model stem from fundamental differences in the models' underlying behavioral assumptions, others arise from arbitrary differences in implementation. Our Monte Carlo experiments revealed that neither model has a clear advantage over the other in the recovery of legislator locations or roll‐call midpoints in either large or small legislatures.     

Do Campaign Donors Influence Polarization? Evidence from Public Financing in the American States

Does the source of campaign funds influence legislative polarization? We develop competing theoretical expectations regarding the effects of publicly financed elections on legislative voting behavior. To test these expectations, we leverage a natural experiment in the New Jersey Assembly in which public financing was made available to a subset of members. We find that public financing exerts substantively negligible effects on roll‐call voting. We then find a similar result in an examination of state legislatures. We conclude that, counter to the logic of the US Supreme Court, pundits, and reformers, the source of campaign funds exerts minimal influence on polarization.     

Uncertainty and Roll‐Call Voting in Lame‐Duck Sessions of the U.S. House, 1969–2010

Lame‐duck sessions of Congress have become increasingly common of late. Such sessions are marked by higher levels of ideological and participatory shirking among departing members, creating a more uncertain legislative environment. I investigate the consequences of such shirking on coalition formation and roll‐call behavior. I analyze House roll‐call votes held in the 12 congresses that convened lame‐duck sessions from 1969 to 2010 (91st to 111th Congresses) to assess how roll‐call behavior changes across sessions. I find subtle but statistically significant changes across sessions consistent with claims regarding greater uncertainty in roll‐call voting in lame‐duck sessions.     

The Role of Party: The Legislative Consequences of Partisan Electoral Competition

We examine the proposition that incentives for legislative organization can be explained by the nature of electoral competition. We argue that legislators in environments where parties are competitive for majority status are most likely to have delegated power to their leadership to constrain individualistic behavior within their party, which will in turn increase the spatial predictability of individual voting patterns. Using roll‐call votes and district‐level electoral data from the U.S. state legislatures, we show empirically that increased statewide interparty competition corresponds to more predictable voting behavior overall, while legislators from competitive districts and those in the minority party have less predictable behavior.     

Party Pressure in the U.S. State Legislatures

We extend Ansolabehere, Snyder, and Stewart's (2001) method of measuring party influence over roll‐call voting to the comparative state legislative context. Examining 27 state lower chambers, we find that overall parties exert detectable influence on 44% of all roll calls and 69% of close votes, but that the incidence of party influence varies strongly across chambers. Taking advantage of the comparative leverage the state context brings, we find that party influence responds significantly to measures of legislative careerism and state socioeconomic diversity, with majority size playing some role. The effect of preference polarization is complicated and conditioned by challenges facing the legislature, and we find results both challenging and conditionally supporting the conditional party government account.     

Party Voting Cohesion in Mixed Member Legislative Systems: Evidence from Korea and Taiwan

How do mixed‐member legislative systems influence legislator voting? While the literature remains inconclusive, this article suggests party influence as an intervening variable. Through an analysis of roll‐call data from Taiwan and Korea, no deviation is evident between district legislators and legislators elected by proportional representation. Further disaggregation of what it means to vote against one's party again finds little evidence of a tier distinction, while party variables remain significant. The findings are suggestive of a contamination effect between tiers, consistent with the influence of parties.     

After Enlargement: Voting Patterns in the Sixth European Parliament

We examined how voting behavior in the European Parliament changed after the European Union added ten new member‐states in 2004. Using roll‐call votes, we compared voting behavior in the first half of the Sixth European Parliament (July 2004‐December 2006) with voting behavior in the previous Parliament (1999–2004). We looked at party cohesion, coalition formation, and the spatial map of voting by members of the European Parliament. We found stable levels of party cohesion and interparty coalitions that formed mainly around the left‐right dimension. Ideological distance between parties was the strongest predictor of coalition preferences. Overall, the enlargement of the European Union in 2004 did not change the way politics works inside the European Parliament. We also looked at the specific case of the controversial Services Directive and found that ideology remained the main predictor of voting behavior, although nationality also played a role.     

Party Unity in the Swiss Parliament: The Electoral Connection

This study investigates the connection between legislative and electoral politics in Switzerland. The authors postulate that party unity is higher in an election year, and more specifically in votes on issues that are important for the party platform and that are of greater visibility to voters. The authors analyse the entire voting record of the Swiss parliament (lower house) on legislative acts between 1996 and 2007, which consists of roll call votes as well as unpublished votes. The authors find a strong effect of elections on voting unity among certain parties, and also find encouraging support for the hypotheses that this effect is mediated by the visibility of the vote and related issue salience.     

The Contribution of Comparative Research to Measuring the Policy Preferences of Legislators

Comparative legislative research has contributed to an examination of the validity of roll‐call votes as measures of legislators' policy preferences. It has prompted an awareness of the influence of legislative structure on the composition of the voting record. Comparative research on members' ideal points has confronted the problems of selection effects, abstentions, the influence of the agenda setter, and the effect of party strategy. It has encouraged the search for alternate measures of members' preferences, including members' speech, cosponsorship, survey responses, and party manifestos. In the non‐American setting, ideal points have been regarded as group‐level, as well as individual‐level, variables. The game‐theoretic approach to the study of legislatures has led to the formulation of hypotheses relating legislative structure to members' ideal points.     

The Statistical Analysis Of Roll‐Call Data: A Cautionary Tale

Roll‐call voting and congressional procedures are two of the most heavily studied aspects of the U.S. Congress. To date, little work has focused on the effect of procedures on the composition of the roll‐call record. This article takes a step in this direction by demonstrating the effect of chamber rules and institutional constraints on House and Senate roll‐call data, as well as on the inferences that scholars have drawn from the roll‐call record. More specifically, I focus on recent efforts to measure party effects and ideological alignments, and I demonstrate that the composition of the roll‐call record can affect these measures.     

Using Cosponsorship to Estimate Ideal Points

Ideal point estimates based on roll‐call vote results have provided leverage for a variety of theory testing efforts. Recently, scholars have suggested using cosponsorship data as a proxy for roll‐call votes. Conceptually similar to roll‐call votes, cosponsorship data are appealing for a variety of reasons. However, the data‐generating process for cosponsorship is untheorized and little studied. We examine the properties of ideal point estimates from cosponsorship data. We find that the ability to estimate ideal points from cosponsorship data is contingent on the underlying data‐generating process; reliance on such measures requires strong and often unrealistic assumptions.     

State‐Level Institutional Effects on Legislative Coalition Unity in Brazil

How do subnational factors affect the proclivity of legislators from the same party or coalition to vote together? We estimate the effects of two institutional forces operating at the state level—intralist electoral competition and alliance with governors—on voting unity among coalition cohorts to the Brazilian Chamber of Deputies. Larger cohorts, in which the imperative for legislators to distinguish themselves from the group is stronger, are less unified than smaller cohorts. We find no net effect of alliance with governors on cohort voting unity. Governors are not dominant brokers of legislative coalitions, a result suggesting that the net gubernatorial effect is contingent on factors that shape governors' influence relative to that of national‐level legislative actors.     

Party Differentiation in Congress

Abstract At times, the American political parties are so close in terms of policy positions that critics denounce the lack of a “dime's worth of difference” between them. At other times, the gap between them on a left‐right dimension is huge. How can we explain this variation? We argue that parties can behave rationally as collective units, and that shifts in divergence and convergence can be explained as rational responses to changes within governmental institutions and to shifts in conditions outside. We analyze this argument using adjusted ADA scores (Groseclose, Levitt, and Snyder 1999) to compare voting score differences between the Democratic and Republican parties in Congress from 1952 to 1996. We pose specific hypotheses for potentially important factors shaping party behavior and test them with a multivariate model. Our results support the argument that the variation in the behavioral gap between the two parties in Congress can be explained as rational party responses to internal and external stimuli.     

To Simulate or NOMINATE?

Carroll et al. (2009) summarize the similarities and differences between the NOMINATE and IDEAL methods of fitting spatial voting models to binary roll‐call data. As those authors note, for the class of problems with which either NOMINATE and the Bayesian quadratic‐normal model can be used, the ideal point estimates almost always coincide, and when they do not, the discrepancy is due to the somewhat arbitrary identification and computational constraints imposed by each method. There are, however, many problems for which the Bayesian quadratic‐normal model can be easily generalized, so as to address a broad array of questions and take advantage of additional data. Given the nature and source of the differences between NOMINATE and the Bayesian approach—as well as the fact that both approaches are approximations of the decision‐making processes being modeled—we believe that it is preferable to choose the more flexible Bayesian approach.