UC Davis

The relative frequency of constitutional amendment is often attributed to the degree of rigidity implied by a constitution’s formal amendment rule. However, some constitutions with an apparently high bar for change see amendments on a regular basis, and vice versa. This dissertation argues that part of the explanation lies veto player settings, a count of veto players produced by the interaction of the party system and the decision rule. This novel approach to veto player analysis, a refinement of Tsebelis’ (2000) framework, reformulates veto player theory to incorporate more clearly the role of intransitivity and offers a measurement design which is more consistent and parsimonious.Using cross-sectional analyses of amendments to national constitutions, I find that higher numbers of veto players are correlated with a lower likelihood of amendment in a given legislative period, even when controlling for the amendment rule. An analysis of US state constitutions suggests a similar pattern where bipartisan support is required to amend: the higher the largest party’s seat share, the higher the likelihood of amendment.