Voting Rules, Legislative

Legislative voting rules are the rules that govern the lawmaking process, as opposed to the voting rules that govern the election of representatives to lawmaking bodies. There are two kinds of rules that govern the lawmaking process. First, there are rules that define and regulate the lawmaking bodies and the relationships between them (“constitutional rules”). These rules determine the number of legislative chambers, their relative powers, and their relationship to the executive, among other things. Second, there are rules that govern the internal working of the legislative bodies (“parliamentary rules”). These rules cover matters such as control of the legislative agenda and the committee system and are usually made within the legislature. In this entry, we will discuss the theory of voting, constitutional rules and their effects, and finally parliamentary rules.

The study of the rules of lawmaking can be traced back at least as far as Aristotle. Although there are exceptions, traditional approaches to legislative rules have tended to be descriptive and formal, drawing heavily on constitutional law. As political science took a more behavioral turn from the 1950s, many scholars put less emphasis on formal rules, as these rules did not seem to have much effect on how political agents actually behaved. However, approaches based on social choice and rational choice theory (the “new institutionalism”) did give a central place to formal rules and provided a link between these rules and behavior. Social choice theorists characterized the mechanical properties of voting rules and found these often produced counterintuitive results. Rational choice theorists considered how maximizing agents would act within a framework of formal rules. The key insight was that small changes in seemingly unimportant rules could have very large effects on predicted behavior in equilibrium.

There has also been a growth in comparative empirical work on political institutions. Recent work has considered the effect of differences in constitutional rules (and to a lesser extent, parliamentary rules) on policy outcomes such as redistribution, state size, and growth. These various approaches to legislative voting rules are likely to be complementary. For example, rational choice approaches emphasize the importance of small, seemingly insignificant rules; identifying these rules in specific legislatures requires that someone do “thick” descriptive work.