Testing the Law-Making Theories in a Parliamentary Democracy: A Roll Call Analysis of the Italian Chamber of Deputies (1988–2008)

The theoretical efforts in the rational choice approach to explain the law-making process in United States Congress have been increasingly matched by attempts to test the relative explanatory powers of different theories (Cox and McCubbins 2005; Krehbiel et al. 2005). No such effort has so far been made by scholars of parliamentary democracy, and this chapter tries to fill this gap. We present a typology of law-making models in parliamentary democracies based on the distribution of agenda-setting and veto power in the legislative arena. This allows us to contrast a particular adaptation of the procedural cartel model with two different versions of the veto player theory (Tsebelis 2002).Using the roll calls of 10th to 15th Italian legislatures, we evaluate, via cut points distribution, the explanatory power of these law-making models under a large variety of political circumstances (different party systems, different legislative sponsorship as well as all possible types of government format).