When Congress Prevails: Veto Overrides and Legislative Fragmentation in Multiparty Legislatures

• Published date: 01 December 2024
• DOI: http://doi.org/10.1177/10659129241268822
• Author: Pablo Valdivieso-Kastner,Sergio Huertas-Hernández
• Date: 01 December 2024

Article

Political Research Quarterly

2024, Vol. 77(4) 1333–1349

© The Author(s) 2024

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DOI: 10.1177/10659129241268822

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When Congress Prevails: Veto Overrides

and Legislative Fragmentation in

Multiparty Legislatures

Pablo Valdivieso-Kastner

1

and Sergio Huertas-Hern´

andez

2

Abstract

This study delves into the determinants of legislative overrides in multiparty legislatures, with a specif‌ic focus on the

inf‌luence of partisan fragmentation within congress. Utilizing an original dataset spanning from 1995 to 2017, we examine

the cases of Ecuador and Peru. Our argument posits that during lawmaking, a dispersed and fragmented party system

prevents the president from anticipating the preferences of the congressional pivotal party. In such a scenario of in-

complete information, the president’s capacity to introduce selective incentives through vetoes is limited. In this way, the

president is less likely to break the congressional majority supporting a bill. Consequently, the vetoed bill becomes less

acceptable compared to the original statute. This, in turn, provides the congressional majority with increased incentives

to uphold the original bill, elevating the likelihood of a legislative override. In alignment with this rationale, our f‌indings

indicate that an increase in the effective number of parties (ENP) has a positive and signif‌icant impact on the probabil ity of

a legislative override. Additionally, our evidence underscores a noteworthy contrast between the relativelyhigh rate of

legislative overrides in Latin America and f‌indings for the US case.

Keywords

legislative override, effective number of parties,Ecuador,Peru

Introduction

This paper studies what happens to bills after receiving a

veto. Following a presidential veto, Congress decides to

override or repass the bill. Typically,overri ding requires a

larger voting majority than repassing. For this reason,

overrides tend to be uncommon events, yet their sheer

possibility compels presidents to consider partisan con-

gressional composition before issuing a veto. This task is

straightforward before a bipartisan congress where

parties’preferences tend to be stable. This is not always

the case. Presidents often interact with multiparty legis-

latures with switching platform positions, which further

complicates presidential considerations to prevent Con-

gress from opposing his veto. Since rules and partisan

composition shape legislative outcomes, studying over-

rides in multiparty settings is crucial to understanding the

last stages of the executive-legislative bargaining process.

How prevalent are overrides? Under what conditions

do legislatures override bills? Do some congresses

override more than others? Sequential veto bargaining

models developed to explain the US case suggest that

override attempts are much more likely when the oppo-

sition controls both chambers of Congress and increase

with legislative signif‌icance (Cameron, 2000,2009).

There are reasons, however, to question whether this

theory extends to other presidential countries. For in-

stance, Latin American presidential democracies differ

from the US model of presidentialism in at least two

crucial aspects. First, these presidents are typically en-

dowed with signif‌icant prerogatives to affect the law-

making process. These agenda-setting prerogatives

extend to the veto process (Tsebelis and Alem´

an, 2005).

For example, most presidential constitutions allow

1

Department of Politics and International Relations, University of

Oxford, Oxford, UK

2

Instituto de Ciencia Pol´

ıtica, Pontif‌icia Universidad C´

atolica de Chile,

Macul, Santiago, Chile

Corresponding Author:

Pablo Valdivieso-Kastner, Department of Politics and International

Relations, University of Oxford, Manor Rd, Oxford OX1 3UQ, UK.

Email: pablo.valdiviesocarrillo@politics.ox.ac.uk

presidents to veto parts of the bill, and in some cases, the

president is allowed to introduce amendments to vetoed

bills, which Congress may accept or reject before moving

to an override vote (Alem´

an and Schwartz, 2006;Palanza

and Sin, 2020). Second, Latin American Congresses tend

to be much more fragmented than the US Congress.

Moreover, in several countries, fragmentation varies from

one period to the next (Kitschelt et al., 2010;Mainwaring,

2018;Pereira and Melo, 2012;Saiegh, 2009). If institu-

tional and partisan conf‌igurations matter, then these dif-

ferences will be highly consequential during inter-branch

legislative bargaining.

This article advances a counterintuitive alternative to

Cameron’s models. We argue that variations in the ef-

fective number of parties inf‌luence the likelihood of an

override. Using a novel data set from two presidential

multiparty countries, Ecuador and Peru, we illustrate how

this mechanism works. We posit that, during lawmaking, a

dispersed and fragmented party system hinders presi-

dential capacity to anticipate congressional median

voter’s preferences. Such an incomplete information

scenario reduces the president’s ability to, through his

veto, introduce selective incentives to break the con-

gressional majority that sustains a bill. The resulting

vetoed bill will tend to be less acceptable vis-`

a-vis the

original statute. Thus, the congressional majority will

have more incentives to sustain the original statute,

thereby increasing the probability of an override.

This paper offers two key contributions to the broader

study of legislative politics in multiparty presidential

systems. First, amidst scarce comparative analysis of the

determinants of legislative overrides, it advances the

debate to two cases of presidential multiparty systems.

Since the specialized literature focuses on the paradig-

matic US case, this paper extends our knowledge about

the lawmaking process under a more varied institutional

and partisan setting. Second, this paper offers new em-

pirical evidence covering 15 administrations across

20 years in Ecuador and Peru (N= 1,910). In addition, the

main f‌inding highlights the relevance of studying legis-

lative fragmentation as a determinant of congressional

outcomes in multiparty presidential democracies. This

evidence provides comparative advantages to other stu-

dents of legislative politics inasmuch as almost a quarter

of the countries worldwide have multiparty presidential

systems.

This study unfolds as follows. First, we review the

main literature on vetoes and overrides in the context of

presidential systems. Here, we consider the necessity of

extending our understanding of legislative override dy-

namics outside the United States. Next, we propose some

working hypotheses and variables derived from the pre-

vious section. Third, we introduce our cases and describe

details about our research design. Subsequently, we test

our hypotheses using logistic regression models and

discuss their main results and implications. Finally, we

outline our main conclusions and some notes for a sub-

sequent research agenda.

What We Know About Vetoes

and Overrides?

The Federalist papers anticipated presidential veto as one

of the most powerful tools to inf‌luence the legislative

process (Hamilton, Madison, and Jay, 2009[1788]). Since

then, the literature interested in executive-legislative re-

lations has conveyed a wealth of ideas regarding veto

power and congressional override, chief‌ly in the Ameri-

can political system (McCarty, 1997;McGrath,

Rogowski, and Ryan, 2018). Nonetheless, other presi-

dential systems –for example, Latin America and Eastern

Europe –have not followed the same tradition. Such

systems seem to work under a different logic (K¨

oker,

2017;Tsebelis and Alem´

an, 2005;Tsebelis and Rizova,

2007). This section reviews the main contributions around

the presidential veto and legislative override dynamics

while pointing out some limitations.

The literature exploring presidential veto and override

is uneven. While research on veto is theoretically and

methodologically rich (Cameron 2000;Cameron and

McCarty, 2004; provide a comprehensive summary),

our knowledge on override is scant. Research on the

conditions that inf‌luence legislative override has been

approached tangentially as part of the veto process

(Cameron, 2012;Gilmour, 2002;McCarty and Poole,

1995). Given the connection between veto and over-

ride, these works assume that a valid theory should ex-

plain both processes (Copeland, 1983). In addition,

theoretical US veto bargaining models predict override

success rates in around 50% of cases (Martin, 2012).

Empirical evidence, nonetheless, reveals a 12.88%

override rate, which is much lower than theoretical ex-

pectations (Bridge, 2014).

Although both veto and override are part of the law-

making process, they do not follow the same causal ra-

tionale. A vetodecision hingesonly onthepresident’s

choice, while an override requires the agreement of a

collegiate body representing diverse preferences. In this

sense, legislators must coordinate when attempting to

override a bill; failure in this endeavour results in ac-

cepting a presidential veto. Common key assumptions of

these models are that the spectrum of legislative prefer-

ences is distributed within a bipartisan legislative

framework and that both the Congress and the President

possess enough information from each other. However,

most presidential regimes worldwide are rather multiparty

systems where near-perfect information is rather scarce.

1334 Political Research Quarterly 77(4)