Dividing Parliament? : Italian bicameralism in the legislative process (1987-2006)

Italian bicameralism is a constitutional feature that is quite often the object of criticism from both politicians and scholars. It is also a somewhat neglected topic within Italian political science. The main aim of the present article is to evaluate the level of congruence between the two chambers of Italian Parliament, using original data on legislative activity in the last legislature of Italy’s First Republic (the 10th Legislature) and the last two Legislatures of the Second Republic (the 13th and 14th Legislatures). Regardless of the measurement we employ, our study clearly shows that the congruence between the two chambers has declined. As a careful empirical analysis suggests, this phenomenon cannot be solely accounted for by the difference in distribution of party seats or by changes to the law-making rules in the two chambers. The article hypothesizes that the diminishing intraparty cohesion could be the main explanatory factor of such dynamics.