Decision Making in Political Systems: Veto Players in Presidentialism, Parliamentarism, Multicameralism and Multipartyism

The article compares different political systems with respect to their ability to produce policy change. It sets out the basic idea of a "veto player," or those individuals or collective actors whose agreement is required for any policy change. Two categories of veto players are identified in the article: institutional (which exist in presidential systems) and partisan (which exist in at least parliamentary systems). According to the author, the potential for policy change decreases with the number of veto players, the greater the difference between policy positions among veto players, and the greater the difference in the policy positions among the constituent units of each veto player. The author suggests that this study, which reflects the empirical data concerning policy changes in different political systems, would be helpful in predicting government and/or regime instability.