Adrian Vermeule, author of Mechanisms of Democracy and co-author with Eric Posner of Terror in the Balance: Security, Liberty, and the Courts, is a Professor of Law at Harvard Law School. (The article below draws upon material in Chapters 3 and 4 of Adrian Vermeule, Mechanisms of Democracy: Institutional Design Writ Small, and upon Adrian Vermeule, “Absolute Majority Rules,” forthcoming in the British Journal of Political Science ( Cambridge University Press, October 2007)).
Many institutions, public and private, use non-majoritarian voting rules for many issues. Supermajority rules, which require more than 50%+1 of the votes in order to change the status quo, are familiar; an example is the filibuster rule in the United States Senate, where 60 votes are necessary to force “cloture,” that is, to close debate on an issue. Less familiar are submajority voting rules, which allow less than 50% of the votes to change the status quo; an example is the “Rule of Four” on the Supreme Court of the United States, which says that the Court will take up a case so long as at least 4 of the 9 Justices vote to do so. When five justices vote against taking up a case and four vote in favor, the four win.
Interestingly, however, the principle of majority voting retains a certain psychological pull – a political and moral force, in the French sense of “morale.” Even where the nominal voting rules of an institution are non-majoritarian, actors frequently make political hay out of the way the majority votes. Actors who failed to carry a proposition by a supermajority can claim a “moral victory” if they got a majority of the votes, as two episodes involving George W. Bush illustrate. In 2003, when it was clear that the United Nations Security Council would not vote unanimously to authorize the invasion of Iraq, the Bush administration made great efforts to obtain a majority of the council votes; though obtaining a majority would have no legal effect, the administration felt it would produce political benefits. Conversely, however, when Al Gore won a clear popular majority in the 2000 election but narrowly lost the electoral college, the result cast a political and moral cloud over Bush’s first term. Many claimed that the failure to obtain a majority of the votes brought Bush’s legitimacy into question.
The claim of moral victory can be spun in other directions as well. Recently, in a crucial cloture vote on an immigration bill in the Senate, 46 senators voted for cloture while 53 voted against. The Democratic leader who had brought up the bill, Senator Harry Reid, decried “obstruction,” but opponents and commentators undercut this claim by pointing out that the bill did not even obtain a majority in its favor, let alone the necessary supermajority.
Sometimes the moral force of majority rule is even politically decisive. In a recent series of decisions, the Supreme Court has voted for conservative results by a 5-4 majority. The majority is in place because Justice Samuel Alito replaced the somewhat more liberal, or unpredictable, Sandra Day O’Connor. The puzzle is that when the Senate voted to confirm Alito in January 2006, there were 42 no votes. Why then did the 42 not filibuster – an action which, under the Senate rules, requires only 40 votes to succeed? Two related reasons explain the puzzle. First, there was an implicit threat that the Senate majority would exercise the “nuclear option” by amending or simply ignoring the relevant rules, thereby overriding the filibuster. Second, the Bush administration and the (then-extant) Republican majority were scoring political points with a charge that the Democratic minority should “give Alito an up-or-down vote.” In other words, there was political pressure to use majority voting to settle the case, despite the nominal availability of a supermajority blocking tactic. The example is not atypical; legislation does with some frequency pass the Senate with more than 40 no votes.
Overall, then, the principle of majority voting retains real force even when institutions have nominally set up nonmajority voting rules. Why does majority rule have this moral force? For one thing, majority rule has the unique mathematical property that it is the only voting rule that satisfies anonymity (Jack’s vote is as good as Jill’s), neutrality (no thumb on the scale for the status quo, or for any other possible result), and two other technical conditions, as the mathematician Kenneth May showed. Furthermore, where there is a right answer to the decisionmaking problem, and voters are on average at least slightly better than random guessers, majority rule gives the best chance of obtaining the right answer; this result is known as the Condorcet Jury Theorem. Most important of all, perhaps, is the sheer simplicity of majority rule. Nonmajoritarian voting rules often take complex forms and rest on complex justifications. Boundedly rational voters and political publics may not appreciate those justifications, whereas majority rule is a natural psychological focal point: more beats fewer.
Given the moral force of majority rule, institutional designers who want to empower minorities might look for close substitutes for supermajority rules – substitutes that do not trigger the political and moral opprobrium that often constrains nonmajoritarian voting. One possibility is an “absolute majority rule,” which requires a majority of all eligible votes, rather than a simple majority of the votes cast. Although both simple majority rule and absolute majority rule use “majority voting,” the latter counts abstentions as no votes, and thus has supermajoritarian effect. In a legislature with 100 voting members, if 40 vote yes, 20 vote no, and 40 are either absent or abstain, the bill passes under simple majority rule, because it obtained a majority of the 60 votes cast. By contrast, the bill fails under an absolute majority rule, because less than 51 votes — a majority of all those that could have been cast — were actually cast in favor of the bill. Here the political charge of minority obstruction is harder to make out than under a regular supermajority rule like the filibuster; opponents of the bill can say, quite truthfully: “hey, you didn’t get a majority.”