George Tsebelis

George Tsebelis is an American political scientist who specializes in political systems and formal modeling. He is currently Anatol Rapoport Collegiate Professor of Political Science at the University of Michigan.

He received undergraduate degrees in engineering from the National Technical University of Athens and in political science from Sciences Po. He received a doctorate in mathematical statistics from Pierre and Marie Curie University and one in political science from Washington University in St. Louis. Tsebelis was elected as a Fellow of the American Academy of Arts and Sciences as part of the Academy's 2016 class.

Tsebelis developed the theory of "veto players", set out in his best known work, Veto Players: How Political Institutions Work (2002)

The ‘veto players’ concept is an old one, dating back at least 2000 years. Tsebelis synthesises and formalizes it. A ‘veto player’ is an individual or collective actor who has to agree for the legislative status quo to change. Tsebelis argues that having many veto players makes significant policy changes difficult or impossible. Tsebelis also predicts that systems with a high number of veto players will pass few significant laws and will tend to high deficits (as the veto players need to be bought off). Tsebelis considers two types of veto players: institutional (those officially named somewhere, such as the President, Congress and Senate) and partisan (those whose veto arises from the system but is not one of the rules of the system, such as political parties). Some of these veto players, moreover, can present ‘take it or leave it’ proposals to the other veto players. Tsebelis calls these ‘agenda setters’.

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