Ministerial drift, pork barrel politics or information problems? Why Italian government bills change in the legislative arena (1987-2006)

With very few exceptions, scholars interested in legislative processes pay relatively little attention to the changes made to bills in parliamentary democracies. Comparative research often describes legislative institutions in parliamentary countries as ineffectual vis-à-vis cabinets throughout the lawmaking process (Mezey 1979; Blondel 1995), while rational choice literature focuses more on the formal rules regulating amendatory activity than on amendatory activity in itself (Rasch 1995, 2000). Therefore few studies try to explain how much laws are altered in the legislative arena and why. In this paper, we focus on changes of governmental legislation in Italy. We consider as dependent variable the modifications occurring during the legislative process, and we discuss a number of explanatory hypotheses both drawn on the existing scholarship and deduced from our original conjectures. Changes to governmental bills may stem from the ideological conflict between coalition partners over the accomplishment of the agreed-on policy compromise (Martin and Vanberg 2005), or from the conflict between legislators over the distribution of benefits among their constituencies (Weingast, Shepsle and Johnsen 1981; Masciandaro 1996). Also, government bills can be altered because governing parties choose to use the assembly - instead of the cabinet - as the arena where to debate and define more precisely the content of legislation. This may occur because at the cabinet level actors have limited information about other actors’ preferences and the effects of laws. In order to evaluate these arguments, we develop a measure of the level of modifications that is based on the textual comparison between the initial bill and the final law. Our original dataset comprises all the governmental laws introduced in the lower chamber between 1987 and 2006. This time span covers both the so-called Italian ''First'' and ''Second Republic'', allowing to assess the impact of fundamental changes in the party system dynamics.