Doctoral Dissertations

Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


New York University


Department of Politics

First Advisor

Alastair Smith, Ph.D.


pre-electoral coalitions, political parties, game theory, comparative politics

Subject Categories

Political Science


Political parties who wish to exercise executive power are typically forced to enter some form of coalition. Parties can either form a pre-electoral coalition prior to an election or they can compete independently and enter a government coalition afterwards. Although there is a vast coalition literature, there are no theoretical or empirical studies of coalitions that form prior to an election. This dissertation seeks to redress this imbalance in our knowledge of coalitions by explaining the variation in electoral coalition formation.

The existing literature implicitly suggests that pre-electoral coalition formation is a simple function of electoral rules: the more disproportional the electoral system, the more likely a pre-electoral coalition is to form. I reframe the notions in the literature as testable hypotheses, using an original dataset comprising all legislative elections in 25 countries between 1946 and 2002. I find considerable support for the following hypothesis: pre-electoral coalitions are more likely to form in disproportional electoral systems if there are many parties. However, this result does not explain temporal variation in pre-electoral coalition formation, and it ignores the obvious distributional consequences that must be overcome when electoral coalitions are formed.

I develop a more nuanced explanation of electoral coalition formation using a finite two-player complete-information bargaining game that generates implications concerning the probability of pre-electoral coalition formation. The plausibility of the model is examined in the context of in-depth case studies of pre-electoral coalition formation in the French Fifth Republic and in South Korea.

Finally, I test the model's hypotheses using a random-effects probit model with an original dataset containing information on potential coalition dyads in 20 industrialized parliamentary democracies from 1946 to 1998. The results support the hypotheses derived from the model. Ideological compatibility increases the likelihood of forming an electoral coalition, as do disproportional electoral institutions. Parties are more likely to form an electoral coalition if the potential coalition size is be large (but not too large) and if the coalition members are of similar electoral size. Finally, electoral coalitions are more likely if the party system is polarized and the electoral institutions are disproportional.



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