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

• Author: Juan Pablo Micozzi,Sebastian Saiegh,Eduardo Alemán,Pablo M. Pinto
• Date: 01 May 2018
• DOI: http://doi.org/10.1111/lsq.12182
• Published date: 01 May 2018

EDUARDO ALEM

AN

University of Houston

JUAN PABLO MICOZZI

Instituto Tecnol

ogico Aut

onomo de M

exico

PABLO M. PINTO

University of Houston

SEBASTIAN SAIEGH

University of California at San Diego

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.

For about a century, scholars have argued that legislative behavior

is affected by both party and constituency inf‌luences. Understanding the

relative impact of these different sources of inf‌luence sheds light on the

nature of representative government as well as on the strength of political

parties. Data constraints, however, have made it diff‌icult to determine

how partisan loyalty and ideological disposition affect legislative voting.

The f‌irst challenge is the inability to observe ideology. Recorded

votes are the most commonly used measure of legislators’ policy prefer-

ences. Researchers have used a legislator-specif‌ic constant or f‌ixed effect

for each legislator as an indicator of personal ideology (Levitt 1996;

Ramey 2015). The use of roll calls to impute policy positions, however,

is problematic because legislators’ voting patterns do not necessarily

reveal their sincere ideological leanings (Krehbiel 2000). Moreover, in

LEGISLATIVE STUDIES QUARTERLY, 43, 2, May 2018 245

DOI: 10.1111/lsq.12182

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C2017 Washington University in St. Louis

most legislatures, the main dimension of conf‌lict is the government-

opposition divide, confounding the effect of ideology and party inf‌lu-

ence on legislators’ votes. Therefore, assessing the effect of partisanship

and ideology on roll-call votes requires measurements of ideology that

are constructed independently of the votes themselves. To overcome this

problem, scholars have recently moved to surveying legislators as a way

of recording their policy preferences.

1

The f‌inal challenge is that constit-

uency inf‌luence is hard to measure. Some studies rely on survey and

statistical techniques to estimate the ideology of survey respondents and

political elites on the same scale using their positions on specif‌ic policy

proposals. Combining legislators’ voting records with the public opinion

data, however, presents signif‌icant practical and conceptual problems in

joint scaling analysis (Jessee 2016; Lewis and Tausanovitch 2013).

Our study overcomes these limitations by using individual-level

data on ideology gathered from public opinion surveys and interviews

with legislators in Argentina. Voters and elected off‌icials were asked to

place themselves, political parties, and prominent politicians on a left–

right ideological scale. We then use the responses to these “bridge” ques-

tions to estimate the preferences of voters and legislators in a common

ideological space using the Bayesian implementation of the Aldrich-

McKelvey method. More importantly, we can match legislators’ survey

responses to their recorded roll-call votes. Doing so enables us to

effectively account for the different sources of inf‌luence on legislators’

voting behavior.

The Argentine case is a good demonstration of the eff‌icacy of our

proposed approach. Existing studies stress the importance of party disci-

pline in the Argentine legislature, which stands in sharp contrast to the

characterizations of party behavior in the US Congress. The literature

also emphasizes the saliency of the government-opposition dimension,

not ideology, as the main dimension of conf‌lict in Argentine legislative

politics. As Hix and Noury (2016) have shown in their cross-national

analysis, the government-opposition divide appears to be the main driver

of voting behavior in most institutional contexts. Thus, this quintessen-

tial party-centered political system provides a suitable setting to study

the importance of constituency and legislator’s ideological leanings on

roll-call voting.

Our results indicate that the weight legislators place on following

the party line is indeed the most signif‌icant determinant of voting behav-

ior in Argentina. The weight of the party position, in contrast, amounts

to 90%. We also f‌ind that ideology plays a role, albeit a minor one,

accounting for only 10% of the weight in a legislator’s voting decision.

Furthermore, the analysis reveals that party inf‌luence follows a

246 Eduardo Alem

an et al.