Stability of Constitutions

Constitution is a pair of rules   ( s ,  S )   that are used in a voting situation. The rule  s  is used to vote about the existing alternatives and the rule  S  is used to vote about changing the rule  s  to some other rule    s '  . We consider what kind of constitutions are likely to emerge as prominent ones if the constitutions contain more than just two rules. In a constitution that contains any number of rules the  n th rule is used to decide about the    n  − 1 th   rule. We define a notion of stability for the constitutions and show that all stable constitutions roughly contain the same rule from    n  = 2   onwards. This is one explanation to the casual observation that the constitutions have usually only two rules.