Clarity vs. Unanimity in Supreme Court Decisions:

In this Slate column, Pepperdine law professor Doug Kmiec decries two recent 5-4 Supreme Court decisions because they undermine Chief Justice Roberts' effort to promote unanimity on the Court, which in turn makes Supreme Court decisions less clear. As Kmiec puts it, "[w]hen the justices work out their disagreements before they write opinions, unanimity has the potential to supply what practicing lawyers (and their clients) most often need—a clear rule."

My view is exactly the opposite: other things equal, the effort to achieve unanimity on the Court actually reduces the likelihood of decisions that establish clear rules. A unanimous decision requires the consent of nine different justices, people who in this day and age have widely differing ideologies and jurisprudential philosophies. An opnion that can command such a broad consensus is likely to require compromise between the preferences of conservative and liberal justices, originalists and living constitutionalists, and so on. Thus, any rule that is agreed to unanimously is likely to be riddled with exceptions, balancing tests, and other compromises that had to be included in order to win the support of all nine justices. This is especially likely to be true if the issue being decided is an important and controversial one that the justices disagree on.

Many of the complex balancing tests and complicated exceptions to rules that legal commentators like to make fun of in Supreme Court opinions are the result of the need to "count to five" - corral the five votes needed to create a binding Supreme Court decisons. Counting to nine is usually likely to require more compromise - and thus more complicated balancing tests and exceptions - than counting to five.

There may be other good reasons to value unanimity in Supreme Court decisions. For example, a unanimous decision that has the support of justices across the political spectrum is probably less likely to be wrong than a 5-4 decision that may have been reached on narrow ideological grounds. But, to the extent that we value clarity in legal doctrine, the quest for unanimity on the Court is likely to do more harm than good.