IDEAS home Printed from
   My bibliography  Save this article

Constituency Size and Stability of Two-Party Systems


  • Arturas Rozenas

    () (Department of Political Science, Duke University, Durham, USA)


This paper investigates how constituency size affects spatial competition in a two-party system with a new entrant. When the electorate is small, two-party systems are stable only if the following conditions hold: the candidates are neither too certain nor too uncertain about voters’ preferences; competition is sufficiently costly; and the candidates have binding policy commitments. Moreover, whenever equilibrium exists in small constituencies, the two parties are considerably polarized. In contrast, when the electorate is large, two-party equilibrium obtains under a much wider set of conditions and exhibits low polarization. The Downsian prediction of two-party convergence and the Duvergerian prediction of plurality rule leading to a two-party system are more robust in larger electorates.

Suggested Citation

  • Arturas Rozenas, 2011. "Constituency Size and Stability of Two-Party Systems," Journal of Theoretical Politics, , vol. 23(3), pages 344-358, July.
  • Handle: RePEc:sae:jothpo:v:23:y:2011:i:3:p:344-358

    Download full text from publisher

    File URL:
    Download Restriction: no


    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:sae:jothpo:v:23:y:2011:i:3:p:344-358. See general information about how to correct material in RePEc.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (SAGE Publications). General contact details of provider: .

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    We have no references for this item. You can help adding them by using this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service hosted by the Research Division of the Federal Reserve Bank of St. Louis . RePEc uses bibliographic data supplied by the respective publishers.