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Institutional Inconsistency and Political Instability: Polity Duration, 1800–2000


  • This article was supported by the Polarization and Conflict Project (CIT-2-CT-2004-506084), funded by the European Commission-DG Research Sixth Framework Program, by the National Science Foundation (SBR 9810092), by the Research Council of Norway, and by the World Bank. We thank the European Union and the Research Council of Norway for their support of the Centre for the Study of Civil War at PRIO. Robert Bates, Patrick Brandt, Bruce Bueno de Mesquita, William Dixon, Nils Petter Gleditsch, Michael Huelshoff, Zeev Maoz, Will Moore, Magnus Öberg, Marc Rosenblum, Bruce Russett, Kaare Strøm, and Suzanne Warner provided valuable comments and suggestions. A replication dataset and Stata do-files, as well as an online appendix containing the results of several alternative models, may be downloaded from

Scott Gates is professor of political science, Norwegian University of Science and Technology (NTNU) and Centre for the Study of Civil War, PRIO, Hausmanns gate 7, N-0186 Oslo, Norway ( Håvard Hegre is research professor, Centre for the Study of Civil War, PRIO, Hausmanns gate 7, N-0186 Oslo, Norway ( Mark P. Jones is associate professor of political science, Rice University, MS 24, Houston, TX 77251-1892 ( Håvard Strand is Ph.D. candidate in political science, University of Oslo, Postboks 1097 Blindern, N-0317 Oslo, Norway (


This article examines how political institutional structures affect political instability. It classifies polities as autocracies or democracies based on three institutional dimensions: election of the executive, constraints on executive decision-making authority, and extent of political participation. It hypothesizes that strongly autocratic and democratic regimes will exhibit the greatest stability resulting from self-enforcing equilibria, whereby the maintenance of a polity's institutional structure is in the interest of political elites, whether through autocratic or democratic control. Institutionally inconsistent regimes (those exhibiting a mix of institutional characteristics of both democracy and autocracy) lack these self-enforcing characteristics and are expected to be shorter-lived. Using a log-logistic duration model, polity survival time ratios are estimated. Institutionally consistent polities are significantly more stable than institutionally inconsistent polities. The least stable political systems are dictatorships with high levels of political participation. The most unstable configuration for polities with an elected executive is one where the executive is highly constrained, but the electorate is very small.

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