Theory and Decision

, Volume 80, Issue 4, pp 561–580 | Cite as

Divergent platforms

  • Sophie Bade


Models of electoral competition between two opportunistic, office-motivated parties typically predict that both parties become indistinguishable in equilibrium. I show that this strong connection between the office motivation of parties and their equilibrium choice of identical platforms depends on two—possibly false—assumptions: (1) Issue spaces are uni-dimensional and (2) Parties are unitary actors whose preferences can be represented by expected utilities. I provide an example of a two-party model in which parties offer substantially different equilibrium platforms even though no exogenous differences between parties are assumed. In this example, some voters’ preferences over the 2-dimensional issue space exhibit non-convexities and parties evaluate their actions with respect to a set of beliefs on the electorate.


Downs model Games with incomplete preferences Platform divergence Knightian uncertainty Uncertainty aversion 


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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  1. 1.Royal Holloway, University of LondonEghamUK
  2. 2.Max Planck Institute for Research on Collective GoodsBonnGermany

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