On June 20th, George Tsebelis delivered a speech upon his acceptance of an honorary PhD by the University of Crete in which he applies the insights of his seminal “veto player” theory to the task of constitutional reform in Greece with a view to reducing the power of extremist parties. We document this speech, previously published in the Greek Political Science Review, in a four-part series.1. Introduction
In almost all my professional life I have been working on the analysis of institutions on the basis of one concept, which constitutes the basis of the development of economics and is becoming more and more prominent in political science: the concept of (Nash) equilibrium. Equilibrium is an outcome that maximizes the utilities of all the actors involved. In different terms, it is the result of optimal action of every player, given the prevailing institutions, and the behavior of all the other actors involved.
Why is equilibrium analysis so crucial in the social sciences? Because, assuming the actors have preferences, and they are rational, each one of them will do the best he or she can to achieve these preferences, or reach as close to them as possible given the rules of the game and the behavior of other players. In other words, equilibrium outcomes will be reached by the rational action of all players involved, and once reached they will not be changed by the action of individual players alone (because each one of them has already adopted optimal behavior to reach the equilibrium point, so, unilateral departure does not promote his goals).
In politics, an important way to “lock” such equilibrium outcomes is to make the change of the status quo more difficult, to require qualified majorities of one (collective) actor or concurrent majorities of different players (in the case, say, of a coalition) to achieve. This has been the subject matter of work presented in my book Veto Players ...Zum vollständigen Artikel