Beyond Presidentialism and Parliamentarism: On the Hybridization of Constitutional Form

Abstract: The presidential-parliamentary distinction is a foundational one in the comparative study of law and politics, at the center of a large theoretical and empirical literature. This paper examines the categories themselves and their internal coherence. Though some debate has concerned the conceptualization of presidentialism, parliamentarism and semi-presidentialism, relatively little attention has focused on measurement. We use new data from a comprehensive survey of constitutions to develop measures of similarity across constitutions. We then examine whether provisions on executive-legislative relations are similar for constitutions within each of the classic categories. Although we find that within-type cohesion is low (at least by our expectations) for all three categories, we find measureable variation in cohesion across type, with presidentialist constitutions being the least cohesive of the three categories. The results also tell us a great deal about the structure of semi-presidentialism, a highly suspect intermediate category in some quarters of the literature. We find semi-presidentialism to be as internally consistent as parliamentarism, but also learn that constitutions in the semi-presidential category bear no noticeable difference from those in the parliamentary category. The measurement exercise thus has important implications for the conceptualization of political systems. Ginsburg Cheibub & Elkins, p.