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in the existing literature. Of course, the presence of this “gap” in the
literature is not suf¬cient justi¬cation for focusing on aggregation (most
topics are neglected by the literature for good reason). Instead, one must
demonstrate that by including aggregation in our analyses, we can
substantially improve our understanding of party systems. I endeavor

These dimensions need not be mutually exclusive. For example, party system nation-
alization is a component of Mainwaring and Scully™s de¬nition of institutionalization.
The extent to which competitors from different districts join together to form
regional or national political parties has been labeled “linkage” by Cox (1997, 1999)
and “aggregation” by Chhibber and Kollman (1998, 2004). The terms are inter-
changeable but for the sake of consistency I will mainly rely on Chhibber and
Kollman™s terminology.
Introduction 3

to do this throughout the book by, ¬rst, highlighting the theoretical
contributions of a focus on aggregation incentives; second, showing how
aggregation and aggregation incentives have shaped the party systems in
two developing democracies (Thailand and the Philippines); and, third,
examining the dynamics of aggregation across a sample of 280 elections
in 46 countries.
When studying party systems, it is important to recognize that there is
no consensus about what an ideal party system should look like. For
example, even though we may agree that hyper-in¬‚ated party systems are
unworkable and that a one-party system calls into question the reality of
democracy, beyond this there is considerable disagreement over the
optimal number of political parties, or whether such an ideal even exists.
This re¬‚ects the fact that institutions necessarily involve trade-offs
between competing objectives (see Powell 2000). For example, fewer
parties can come at the cost of less correspondence between voter and
party positions (Powell and Vanberg 2000). Likewise, larger, more
national parties may undermine the links between politicians and local
constituencies. For this reason, I avoid language that casts greater or lesser
aggregation, fewer or more parties, or more or less nationalization as a
straightforward normative choice.
The remainder of this chapter proceeds as follows. In the next section, I
brie¬‚y review arguments for why voters, candidates, and legislators might
derive bene¬ts from the formation of political parties. I then discuss the
two features of the party system at issue here “ nationalization and the
number of parties “ in more detail. The core of this chapter is a brief
summary of the arguments in this book and a discussion of how a focus on
aggregation and aggregation incentives improves our understanding of
why party systems develop as they do. I then talk about the use of
Thailand and Philippines as cases with which to evaluate the theory. The
¬nal section outlines the contents of the remainder of the book.

1.2 why parties?
Throughout this book, I de¬ne a political party as any group of candi-
dates that contests an election under a common party label (Epstein1967;
Cox 1999).3 A party system is an enduring pattern of intra-party

I recognize parties can be much more than this as well.
Building Party Systems in Developing Democracies

organization and inter-party electoral competition (Chhibber and
Kollman 2004, 4). We know that parties and party systems have real and
important consequences for a variety of outcomes that we care about.
This list includes the health of democratic government (Mainwaring
and Scully 1995), the nature and quality of democratic representation
(Lijphart 1999; Powell 2000), government stability (Sartori 1976; Laver
and Scho¬eld 1990; Mainwaring and Shugart 1997), and the nature of
the policymaking environment and policy outcomes (Alesina, Roubini,
and Cohen 1997; Persson and Tabellini 2000; Franzese 2002; Hicken
2002; MacIntyre 2002; Chhibber and Nooruddin 2004; Hicken and
Simmons 2008). It is understandable then that scholars focus so much
attention on political parties and party systems. It is also no surprise that
constitutional architects and political reformers (in democracies old and
new) often have the party system in mind when (re)designing political
rules and institutions. By adopting certain institutions, they hope, among
other things, to produce a certain type of party system.
This emphasis on political parties and party systems by both
political scientists and political practitioners re¬‚ects the central role
for political parties in modern democratic government. Why and how
parties emerge as the core institutions of modern democracy is the
subject of much discussion in the literature. One way to parse this
literature is to separate it based on the unit of analysis “ voters (citi-
zens), candidates, or legislators (Chhibber and Kollman 2004, 67).
Voter-focused approaches view political parties as the natural out-
growth of shared preferences among subsets of voters (social clea-
vages) (Lipset and Rokkan 1967; Rose 1974; Caramani 2004).4 These
parties endure as long as those preferences remain stable. However,
fundamental changes in those preferences, whether from demo-
graphic shifts, industrialization, postmodernization, or some other
source, generate opportunities for new parties to form (Key 1949;
Schattschneider 1960; LeDuc 1985; Ingelhart 1997).5
A second portion of the literature emphasizes the incentives
for candidates to join with other candidates under a common party
banner. To be elected, candidates must grapple with two collective

For critiques of this literature see Kitschelt (1989) and Bartolini (2000).
The effect of changes in underlying social preferences is mediated through electoral
institutions (Amorim-Neto and Cox 1997; Ordeshook and Shvetsova 1994; Hug
2001; Clark and Golder 2006).
Introduction 5

action problems among their potential supporters (Aldrich 1995).
Given the negligible impact of a single vote on the outcome, why should
potential voters (a) pay the cost of educating themselves about the
available choices (Downs 1957) and (b) bother to vote at all (Downs
1957; Riker and Ordeshook 1968)? Candidates have strong incentives
to help potential supporters overcome these obstacles, and a party can
be an effective tool toward that end. Consider the case of the candidate
who seeks of¬ce merely for the perks and rewards that come with the
position. (I will consider in a moment candidates who have policy
preferences they wish to see adopted.) Parties offer two advantages to
of¬ce-seeking candidates. First, party af¬liation can aid candidates in
establishing a reputation “ a “brand name” “ in the eyes of voters. Party
labels, in other words, can serve as useful information shortcuts,
reducing the information costs to voters and providing candidates with
a core of likely supporters (Campbell et al. 1960; Lupia and McCubbins
1998). Second, candidates can recognize economies of scale through
coordinating with other candidates under a common party label. For
example, if the party were to invest in voter education or work to
increase the turnout of likely party supporters, all candidates on the
party™s ticket would potentially bene¬t.
Gains from economies of scale also play an important role in
explanations of party formation that focus on legislators™ incentives.
Legislators often face tasks that require the help of a large number of
legislators (Cox 1997). Whether it is implementing a policy agenda,
blocking proposals to change the status quo, or gaining access to
the resources of government, large groups are often better able to
accomplish these tasks than smaller groups. More generally, parties
help solve collective action dilemmas for legislators by enabling legis-
lators to enforce agreements to support each others™ bills (and avoid
cycling among various policy proposals) (Aldrich 1995; Jackson
and Moselle 2002) and by providing a mechanism for protecting the
party™s collective reputation and long term interests (Kiewit and
McCubbins 1991; Cox and McCubbins 1993).
To summarize, during elections, political parties provide a means of
aggregating, organizing, and coordinating voters, candidates, and
donors (Chhibber and Kollman 2004, 4). Within the legislature, parties
are vehicles for solving collective action problems and coordinating the
behavior of legislative and executive actors (ibid.). Political parties also
Building Party Systems in Developing Democracies

provide a means for balancing local concerns with national interests
and long-term priorities with short-term political demands.
In new and developing democracies, parties do all these things and
more. Political parties are often the most immediate and potent symbols
of democracy to voters in new democracies and can either bolster
support for democratic norms and institutions or undermine their
legitimacy. Parties are also important for managing the con¬‚ict and
upheaval that are an unavoidable part of democratic transitions and
economic development. Finally, political parties are also key to creating
viable organizational alternatives to military cliques. Without strong
parties and an effective party system, it is more dif¬cult to drive the
military back to the barracks and keep them there. In short, the progress
of democratic consolidation can very much hinge on the kind of party
system that emerges in developing democracies (Sartori 1976, 1986,
1994; Mainwaring and Scully 1995).

1.3 nationalization and the number of parties
Even though party systems have many important features, the chief focus
of this book is on two of those features “ the degree of party system
nationalization and the number of political parties. I de¬ne nationali-
zation as the extent to which parties have broad, national constituencies
as opposed to constituencies that are primarily regional, local, or paro-
chial in nature. With respect to the number of parties in a party system,
they can be “counted” in a variety of ways.6 For the purposes of this
book, I employ the de¬nition used in much of the parties and elections
literature by calculating the “effective number of parties” (ENP) (Laakso
and Taagepera 1979), while recognizing the limitations involved with
this measure (see Dunleavy and Boucek 2003). ENP is de¬ned as 1
divided by the sum of the weighted values for each party. This measure
weights parties according to their size “ parties with large vote shares are
weighted more than parties with small shares.7 If one party captures all
of the votes, then ENP ¼ 1. If n parties have equal vote shares then

For example, in the 1995 Thai election, there were 20 registered political parties, 14 of
which actually ¬elded candidates, 11 of which actually won seats in the National
The weighted values are calculated by squaring each party™s vote share (vj):
ENP ¼ 1/( vj2).
Introduction 7

ENP ¼ n.8 I discuss both the number of parties and nationalization in
turn, starting with the number of parties.

The Number of Parties

We know that the number of political parties in a party system has a
variety of important consequences. The number of political parties affects
such things as coalition stability, government decisiveness, government
credibility, and the likelihood that voters will be able to vote for a party
that is close to their ideal point (Laver and Scho¬eld 1990; Colomer 2001;
MacIntyre 2002). Obviously what is considered an optimal number of
political parties will vary from country to country, expert to expert,
depending on which governance goals we wish to privilege. Some advo-
cate a multiparty system for its representational advantages (Lijphart
1977; Powell 2000; Colomer 2001), whereas others argue that a two-party
(or even a single-party) system has advantage in terms of accountability,
decisiveness, and incentives for moderation (Horowitz 1985; Shugart and
Carey 1992; Reilly 2001).
Within this debate, however, there is considerable consensus that
either extreme in party system size is inimical to effective democratic
governance. Where a single party dominates, we may justi¬ably wonder
whether the system is truly democratic and question the degree to which
elections are free and fair. Likewise, the problematic nature of a hyper-
in¬‚ated party system is a common theme in the comparative politics
literature, although again de¬nitions of what constitutes “too many”
parties may differ.9 An in¬‚ated party system can give rise to a gulf

One can calculate ENP using either the vote share of a particular party or its seat share.
Using votes yields the effective number of electoral parties, whereas the seat share gives
the effective number of legislative parties. I use vote shares unless otherwise noted.
Quotes like these are common in discussions of developing democracies:
Romania: “The large number of political parties often renders the democratic
workings of government immobile. A certain instability has thus become the
hallmark of the government.” (Lovatt 2000)
Kosovo: “There are too many political parties in the Balkans as it is; we have enough
of them for export.” (Quemail Morina, quoted in ERP KiM Newsletters 2004)
Brazil: “The fact is that there are simply too many parties to allow an effective
government to be set up and implement consistent policies based on the national
interest.” (Fitzpatrick 2006)
Gambia: “One of the hard truths of the 2001 elections is that there existed too
many political parties.” (Ceesay 2005)
Building Party Systems in Developing Democracies

between visible and invisible politics (especially when combined with
ideological polarization (Sartori 1976)), undermine cabinet/government
stability (e.g., Laver and Scho¬eld 1990) and make it dif¬cult for gov-
ernments to pass needed policies in a timely manner (e.g., Tsebelis 1995,
2002; Mainwaring and Shugart 1997; Cox and McCubbins 2001;
Franzese 2002). Perhaps, then, it is not surprising that institutional
reforms in existing democracies are often aimed at reducing the number
of parties in the party system (Shugart 2001; Shugart and Wattenberg
2001; Reilly 2006).


A growing number of scholars are focusing on the causes and con-
sequences of party system nationalization (Cox 1997, 1999; Chhibber
and Kollman 1998, 2004; Jones and Mainwaring 2003; Caramani 2004;
Morgenstern and Swindle 2005). The degree of party system nationali-
zation matters for a large number of issues that interest political scientists.
The degree of nationalization communicates important information
about the nature of political parties™ and politicians™ constituency.10
The more nationalized the party system, the larger or broader the
constituency is likely to be, ceteris paribus. In other words, the nature of
the groups and interests to whom parties respond very much depends on
the extent to which parties garner votes nationally (across a country™s
various electoral districts and geographic regions) or draw support from
narrow subnational constituencies.
Whether or not more or less nationalization is preferable is not my
focus here. However, it is worth noting that, like the number of parties,
nationalization embodies a trade-off between competing objectives. If
the goal is to maximize the incentives for political actors to respond to,
promote, and protect broad national interests or to create or maintain a
national identity, then more nationalization is preferable to less, all else
equal. For example, a number of scholars have argued that democratic


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