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America, for example, are by necessity studies of presidential party
systems. Likewise, work on Western European party systems is pre-
dominantly based on the experience of parliamentary (or hybrid)
democracies. By comparing the Philippines presidential system with
Thailand™s parliamentary government, we can consider whether the
nature of executive institutions affects the development of the party
system. At the same time, we can maintain the advantages of staying
within a single region (e.g., the commonalities of history and level of
economy development, as discussed previously). Since much of existing
work on developing democracy party systems focuses on presidential or
hybrid democracies, the case of parliamentary Thailand is especially
The experiences of Thailand and the Philippines can help us develop,
test, and re¬ne our ideas of how the world works, but the theories and
approaches of political science also have something to offer in return.
Speci¬cally, the application of the theory developed in this book to the
cases of Thailand and the Philippines allows me to address a number of
interesting and unresolved empirical puzzles. First, what accounts for
the large party system size and relative lack of nationalization in each
country? Second, why were there historically more parties in
Thailand than in the Philippines? Third, to what do we ascribe the sharp
drop in the number of parties in Thailand in the 2000s? Finally, how
do we explain the increase in the number of parties and the demise
of the Philippine two-party system since the return of democracy in
Using the theory to help answer these questions, I demonstrate that
differences in the extent of aggregation in the Philippines and Thailand
help explain why the Thai party system has more parties than its
Philippine counterpart. I also establish that the deterioration of the
two-party system in the Philippines after the fall of Marcos is primarily
due to aggregation failures “ an explanation that outperforms existing
theories of why this change occurred. I also show that the fall in the
number of parties since 2000 in Thailand is almost completely a
function of improved aggregation. Finally, I demonstrate that the
variation of aggregation over time and cross-nationally is consistent
with the theory of aggregation incentives outlined earlier.
In investigating these empirical puzzles, I consider and reject two
opposing lines of argument about the relationship between the electoral
Introduction 23

and party systems. First, to some the presence of multiple parties in
two countries using majoritarian/¬rst-past-the-post electoral systems
might suggest that theories linking the number of parties to the type of
electoral system are at worse, wrong, or, at best, not applicable to
developing democracies like Thailand and the Philippines. Those who
ascribe to the latter view argue that the assumptions underlying electoral
system theories are problematic in many developing democracies. In
countries like Thailand and the Philippines, poor education and a lack of
access to media raise information costs, while vote buying or the dom-
inance of traditional social networks (e.g., patron-client relationships)
limits voter behavior. Thus voters and candidates do not act in the ways
the theories predict, and we do not see the coordination on a small
number of parties that we see in developed democracies with similar
electoral systems. As plausible as this argument may sound, it does not
stand up to scrutiny in the Thai and Philippine cases. Using data from
Thai and Philippine elections, I demonstrate that coordination by voters
and candidates, and the resulting number of parties, is generally con-
sistent with theoretical expectations. In so doing, I present a novel
analysis of the way in which the block vote electoral system (used by
Thailand) operates to shape the coordination incentives of candidates
and voters.
A second line of argument, rather than dismissing the electoral system
as unimportant, takes the opposite position. Namely, the number of
political parties is primarily a function of the type of electoral system a
country employs.23 As discussed earlier, I argue that even though elec-
toral systems do shape behavior in signi¬cant ways they are only a part of
the story. The number of parties nationally is also a function of coor-
dination by candidates and parties across districts. The analysis of
election results from Thailand and the Philippines demonstrates that
aggregation (or aggregation failure) is a crucial determinant of the
number of parties and the degree of nationalization “ more important in
some cases than the electoral system. This ¬nding supports growing
evidence that very large party systems are large not because of district
level failures but because of aggregation failures.

More accurately, it is a function of the interaction between the electoral system and
underlying social cleavages (Powell 1982; Ordeshook and Shvetsova 1994; Amorim-
Neto and Cox 1997; Clark and Golder 2006).
Building Party Systems in Developing Democracies

Party Systems and Consequences of Institutional Reform

A focus on the Thai and Philippines party systems also allows me to
address the issue of the (unintended) consequences of institutional
reform. I focus on one set of institutional reforms in each country “ the
1987 Philippine constitution and the 1997 Thai constitution. I argue
that institutional reform has indeed produced changes in the party
system, but not always in the way reformers anticipated or intended.
After the fall of Ferdinand Marcos in 1986, a new democratic con-
stitution was adopted. It largely reestablished the rules and institutions
that had existed during the 26 years before the Marcos regime, but with
at least one important exception. The constitution placed a new single-
term limit on the president, a reaction to the Marcos dictatorship,
which proved to have profound, though unintended, consequences for
the party system. Speci¬cally, I show how the introduction of presi-
dential term limits undermined aggregation incentives and prevented
the return of the two-party system. I demonstrate that this account of
party system change in the Philippines logically and empirically out-
performs existing explanations of the demise of the two-party system.
In 1997 Thailand also adopted a new constitution. Among the goals
of the constitutional drafters was a major reform of the party system.
Speci¬cally, they hoped the reforms would lead to fewer, more
nationalized political parties. As a result of the reforms, nationalization
did improve and the number of political parties did in fact fall dramati-
cally in the ¬rst post-1997 election. Even though this was consistent with
the drafters™ goals, I argue that the reduction came about largely for the
reasons they did not anticipate. The decrease in the number of parties had
more to do with new, stronger incentives for cross-district coordination,
an unintended consequence of constitutional reform, than it did with
deliberate changes to the electoral system.

1.6 plan of the book
The remainder of the book is organized into six chapters “ a theoretical
chapter, a large-N comparative chapter, three country-focused compar-
ative chapters, and a conclusion. In Chapter 2, I develop and discuss the
theory of aggregation incentives to be used throughout the rest of the
book. In Chapter 3, I derive a set of hypotheses from the theory outlined in
Introduction 25

Chapter 2, discuss strategies for operationalizing the various dependant,
explanatory (and control) variables of interest, and test those hypotheses
using a dataset of 280 elections in 46 countries. Chapter 4 is the ¬rst of
two chapters grappling with the Thai case. I ¬rst examine within-district
coordination in Thailand and demonstrate that the large number of
parties and lack of nationalization that de¬ned Thailand™s party system
cannot be explained by coordination failures at the district level. In fact,
the prevalence of patron-client links, poorly educated voters, and cultural
differences from Western democracies has not signi¬cantly hindered
intra-district coordination as some may have supposed. Thailand uses
an unusual type of majoritarian electoral system that has rarely been
studied “ the block vote system. As a result, I ¬rst derive a set of
hypotheses regarding the nature of intra-district coordination in Thailand
and test those hypotheses using data from Thai elections. I then demon-
strate that poor aggregation is chie¬‚y responsible for the large number of
parties and lack of nationalization in Thailand.
In Chapter 5, having established that coordination failures are more
prevalent across districts than within them in Thailand, I use the theory
outlined in Chapter 2 to explain the poor aggregation in pre-1997
Thailand. I then focus on the way in which constitutional reform altered
the aggregation incentives for Thai politicians resulting in fewer, more
national parties. I also discuss the way in which the improvement in
aggregation incentives contributed to the rise of Thaksin Shinawatra and
his Thai Rak Thai Party. Finally, I analyze the way in which the 2007
Constitution reforms, adopted in the wake of the 2006 coup, should alter
aggregation incentives moving forward.
Chapter 6 shifts the focus to the case of the Philippines and one of the
most interesting questions in the study of Philippine parties and elections “
the demise of the two-party system in the post-Marcos era. I also draw on
theory to explain an unusual electoral pattern the Philippines “ namely,
that there are fewer parties in midterm legislative elections than when
legislative elections are concurrent with presidential elections. I dub this
the counter-currency effect and note that it is precisely the opposite pat-
tern than that observed in many other presidential democracies (Shugart
1995). The chapter ends with an analysis of the differences between the
Thai and Philippine party systems. The concluding chapter summarizes
the major ¬ndings and offers some directions for further research.

A Theory of Aggregation Incentives

2.1 introduction
Imagine you are a political entrepreneur seeking political power in
pursuit of some goal. This could include everything from pursuing
personal enrichment, to protecting or advancing the interests of a cer-
tain group, to implementing your preferred set of programmatic poli-
cies. As discussed in the last chapter, there are many reasons why, in a
modern democracy, a political party would most likely be your vehicle
for seeking political power in pursuit of that goal. But what factors
dictate the kind of party you choose to join or organize? Speci¬cally,
when would you want to join or form a large, national party, and when
might you be content with belonging to a smaller organization? These
are the questions I seek to answer in this chapter.
To answer these questions, I focus on the incentives of two types of
actors “ ¬rst, political entrepreneurs or nascent party leaders, and
second, candidates for the national legislature.1 Political entrepreneurs

In order to keep the exposition simple I generally treat voters as passive actors “
responding to the incentives in the political environment and the actions of candidates
and political parties. However, as Chhibber and Kollman (2004) show, assigning a more
active role to voters would likely generate similar conclusions since voters respond to
many of the same incentives to which the other actors in my story respond. Speci¬cally,
Chhibber and Kollman demonstrate that where political power and control of resources
are concentrated at the national level of government, voters respond by voting for
nationally oriented parties in a position to compete for that power. Conversely, where
subnational actors control signi¬cant power and resources, voters are more likely to
support smaller local or regional parties.

A Theory of Aggregation Incentives 27

can come of in a variety of types “ they might be the leader of the
political group or faction, the leader of a small or medium-sized
political party, or a notable ¬gure looking to enter politics. The dis-
tinguishing feature of these entrepreneurs is their goal to capture some
share of national executive authority via their position as head of a
political party. I assume legislative candidates, whether in pursuit of
personal, parochial, or policy goals, seek to win a seat in the legislature
and thereafter gain access to the power and resources of government.
Candidates may operate as individuals, or, as in many countries, as part
of political groups, factions, or clans. We can think of these groups as
proto-parties, the building blocks of organized political parties large or
small. Individual candidates must decide with what kind of political
party to ally, and groups of candidates face a decision about whether to
compete as a small, stand-alone party or to ally with other groups of
candidates to form a larger party.
What factors shape the incentives of these two types of actors to
coordinate across districts in national legislative elections?2 This is an
important question. In Chapter 1, I demonstrated that the degree of
cross-district coordination has consequences for a variety of outcomes
we care about. This is because cross-district coordination, or aggre-
gation, helps determine the number of political parties and the degree of
party system nationalization. In this chapter, I present a theory of
aggregation incentives.
In one of the few existing studies of this subject Chhibber and
Kollman (1998, 2004) demonstrate that actors respond to the con-
centration of power and resources at the national level of government
(relative to subnational units). Speci¬cally, aggregation incentives are
positively related to the concentration of power and resources. I label
this vertical centralization. I recognize that the degree of vertical cen-
tralization may shape actors™ incentives to link across districts under a
common party label; however, I argue that a high degree of vertical
concentration is not enough to induce aggregation. Two other factors
play key roles. First, the degree of horizontal centralization “ that is,
the concentration or dispersion of power within the national

When there are two legislative chambers, I focus on the competition for the lower,
primary chamber. I discuss the implications of bicameralism for lower chamber
electoral coordination later.
Building Party Systems in Developing Democracies

government “ also in¬‚uences aggregation incentives. Speci¬cally,
horizontal and vertical centralization interact to determine the payoff
to being the largest party at the national level: the larger the payoff (the
greater the horizontal and vertical centralization), the stronger the
incentives for entrepreneurs to organize large national parties, and for
candidates to link across districts, ceteris paribus. Second, the proba-
bility that the largest party will be able to capture the reins of govern-
ment is another variable that helps shape aggregation incentives.
Indeed, a large potential payoff may do little to induce aggregation
absent some reasonable expectation that those actors who successfully
coordinate will receive that payoff. In short, I argue that aggregation
incentives are a product of two factors: (a) the payoff to being the
largest party at the national level (which itself is a product of vertical
and horizontal concentration), and (b) the probability that the largest
party will be able to capture that payoff.
The chapter proceeds as follows. In the next section, I develop a
theory of aggregation incentives and explain why the addition of the
horizontal centralization variable offers an improvement on existing
models that focus exclusively on vertical centralization. I then explore
the way in which the probability variable (the probability that the largest
party will capture executive power) plays out differently in parliamen-
tary and presidential systems. In parliamentary systems, the question is
whether the largest party gets the chance to form the government and
capture the prime minister™s of¬ce, while in presidential systems the
timing of elections, the number of presidential candidates, and the pres-
ident™s eligibility for reelection are key. The ¬nal section concludes.


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