movements that turn to electoral politics, such as social democratic parties: Lipset
and Rokkan 1987 ; Przeworksi and Spraque 1986 ; and green parties, e.g. Kitschelt
1989 ) or, quite commonly, from the actions of current or hopeful political elites.
The key point here is that, relative to most political institutions, political parties are
shaped as institutions by political actors, often in the same timeframe and by the
actions of the sameWgures who are shaping legislation or other political outcomes.
They are, that is, unusually ‘‘endogenous’’ institutions, and we therefore must keep
in mind that the party institutions (or at least organizations) can be changed with
greater rapidity and ease than virtually any other political organization (Riker 1980 ;
Aldrich 1995 ). To pick one simple example of the power of thinking about
endogenous parties, consider the case of third parties in America. To be sure,
there are the Duvergerian forces at work ( 1954 ;Cox 1997 ). But that explanation is
only why two parties persist, not why the Democrat and Republican parties persist.
The answer to the latter question is that they act in duopoly fashion so as to write
rules that make entry and persistence by any contender to replace one or the other
as a major party all but untenable (e.g. Rosenstone, Behr, and Lazarus 1996 ). Thus,
the makeup of the party system is endogenously determined by the actors already
in it. Indeed, the creation of the majority electoral system itself was the conse-
quence of endogenous choice by partisan politicians in the USA (see Aldrich 1995 ).
2PartySystems
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Most of this chapter looks at the makeup of and/or actions taken in the name of the
political party. It is, in that sense, a microscopic look inside the typical party. No
democracy, however, has only one party. When there are two or more parties in
competition over the same things—control over oYces, over legislation, or over
whatever—we should expect that each party will be shaped in part by its relation-
ship to the other parties. How these parties form a system will not be assessed here,
but we cannot look at the party in and out of the legislature without at least
addressing two points.
TheWrst is that a political system is not truly democratic unless its elections are
genuinely competitive. Competition, in turn, does not exist without at least two
parties with reasonable chances of electoral success. It is often thought that a
Xedgling democracy has not completed its transformation until there has been a
free and competitive election that has peacefully replaced the incumbent party with
one (or more) other parties. This happened, for example, in both Mexico and
Taiwan in 2000 , when erstwhile authoritarian one-party states transformed
political parties in and out of legislatures 557