Majority and supermajority rules: Three views of the capitol

Introduction Legislators act under voting rules that require widely varying proportions of the legislature to agree to pass a law. Sometimes legislators act under simple majority rule. At other times they act under express and stringent supermajority rules, as for instance under the two-thirds rule required for each house to propose constitutional amendments.1 Still at other times, the legislature acts under requirements that may appear to be majoritarian but actually create an effect similar to a mild supermajority rule. Such, for instance, are the rules of "tricameralism" that govern the passage of ordinary legislation in Congress, requiring bills to receive the approval of the House, the Senate, and the President.2 Despite this diversity of voting rules, scholars have spent relatively little time explaining or justifying the patterns that we observe in real world legislatures. In this Article, we attempt to make progress on this important task by exploring the choice between majority and supermajority voting rules. In particular, we attempt to match the voting rule with the circumstance in which it would be desirable. For example, we argue that supermajority rules make sense for the enactment of annual appropriation bills and for constitutional provisions, but not for ordinary legislation that is not subject to special infirmities in the political process. This analysis has both positive and normative aspects. It helps to explain why constitutions often assign different voting rules for the passage of different kinds of legislation, such as requiring a relatively substantial supermajority to enact or amend constitutional provisions. It also helps to make a normative case for the use of certain supermajority rules, such as a supermajority rule for spending legislation.3 This Article, then, attempts to do for the choice of legislative voting rules what the law and economics literature has sought to do for the choice of entitlement rules-to justify which voting rules should be used in different situations much as the law and economics literature has justified which entitlement rules to apply in different situations. The decisions in public law about what legislative voting rule to use are analogous to the decisions in private law about whether to use property or liability rules to protect entitlements and to whom to assign the entitlement. Just as the choice of entitlement rules generates the actions and bargaining that dominate social and economic life, so the choice of legislative voting rules generates the actions and bargaining that dominate political life. More than thirty years ago, Guido Calabresi and Douglas Melamed in a groundbreaking article drew attention to the fundamental choice between property rules and liability rules in protecting private entitlements.4 A bevy of other legal scholars have refined their analysis to take account of complexity and nuance.5 Yet legal scholars have rarely mentioned the no-less-fundamental choice between majority and supermajority voting rules in public law. As Calabresi and Melamed observed, it is transaction costs that raise the stakes as to the choice of entitlements rules.6 In the absence of transaction costs, the assignment of entitlements and the method for protecting them would not matter, since individuals would reallocate the entitlements efficiently.7 Regardless of who was initially assigned the entitlement and what type of protection was employed, individuals would make trades to assure that the entitlement would go to the highest valuing user.8 But the presence of transaction costs turns both the initial assignment of the entitlement and the rule by which it is protected into critical decisions, because transaction costs may block reallocation.9 Thus, scholars have developed many different methods to determine which user should be assigned the initial entitlement and which would be the best rule for protecting that entitlement in order to maximize net benefits. …