A Model of Split-ticket Voting with Uncertainty
Insun Kang
∗
Department of Political Science
University of Rochester
August, 2003
Abstract
This paper models an on-year election in which the presidential and leg-
islative elections are held simultaneously. The president is elected by plurality
rule and each legislator is elected in single member districts by simple plurality
rule. Policy outcomes are a function of not only which party holds the presi-
dency but which party gets the majority of seats in the legislature. Parties are
uncertain about the ideal points of the voters. With this model, we show that
first, there are some ticket-splitters in every equilibrium, and second, there
exists an equilibrium in which moderate voters split their votes between pres-
idential and legislative elections. In addition, when we apply the equilibrium
strategy into two-period election, we find this model also explains the midterm
loss phenomena.
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Introduction
In a democratic government, often more than one office is elected at the same time
and policy outcomes are determined by the interactions between different office hold-
ers. For example, national policies are a function of the bargaining between the
executive and the legislature. If voters care about the policy outcome, then, their
decision on one office is not independent from their decisions on the other offices.
That is, when voters vote for both the president and the legislator, they should con-
sider how their vote for each office will affect the formation of a national policy. By
∗
Paper prepared for the delivery at the 2003 annual meeting of the APSA. I would like
to thank Seok-ju Cho, John Duggan, and Mark Fey for their helpful comments.
Email:
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