Ex Ante and ex Post Voting Power: A Method for Calculating Party Power in Party Government

Jan-Erik Lane, Alexander M. Preker

Department of Political Science, University of Freiburg, Freiburg im Breisgau, Germany.

DOI: 10.4236/sm.2013.32022                

Abstract

As political power tends to be wielded in the form of voting power in the national assembly, especially under the institutions of party government, one needs a method to calculate the voting power of political parties, both longitudinally and for a cross-section of European democracies. This paper suggests such a method, derived from the power index approach in cooperative game theory. The application of the method on the history of democracy in the two German nations results in party scores—mandates, ex ante and ex post voting power—that are much in congruence with the standard interpretations of the interwar period and the post-war politics in these two countries.

Keywords

Party Government; Government Coalitions and Coalitions in the Legislature; Ex Ante and ex Post Voting Power; Penrose-Banzhaf-Coleman Framework; Banzhaf Numbers or Scores; Double Banzhaf Games; Party Government in the Two German Speaking Nations

Conflicts of Interest

The authors declare no conflicts of interest.

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