On learning from others.

• Author: Posner, Eric A.
• Position: Response to article by Nicholas Quinn Rosenkranz in this issue, p. 1281

Some people think that the practices of many courts in many countries, or in many relevant countries, offer helpful guidance to courts in other countries, when those courts are approaching hard or novel questions. (1) In their view, the practices of many courts create a body of law in which other courts should be highly interested. The obvious question is: Why?

In The Law of Other States, (2) we attempt to make progress on this question. Our focus was not principally on the use of foreign precedents in the constitutional rulings of the U.S. Supreme Court. We meant to take that controversial and specialized problem as part of a much more general one, which involves courts in one jurisdiction using the decisions of courts in other jurisdictions. Within the United States, state courts frequently refer to the decisions of other state courts, even when construing state constitutions. (3) The high courts of many nations refer to the decisions of high courts of other nations. (4) The problem is that it is not self-evident that the practices of courts AY should be taken as valuable or informative for court Z. Exploration of that problem might also illuminate the question of whether and when a legislator or administrator in one state should attend to the decisions of legislators or administrators in other states.

Our principal submission was that the problem is helpfully approached through the lens of the Condorcet Jury Theorem (CJT). If many people have (independently) decided that X is true, or that Y is good, the CJT gives us reason, under identifiable conditions, to believe that X is true and that Y is good. In our view, the CJT helps to formalize the intuition that if most courts have decided in favor of a certain result, other courts (and perhaps legislators and executive officials as well) should pay attention to their decisions. But if the CJT provides the strongest reason for the practice of consulting the law of other states, it also offers a series of important cautionary notes. If the courts of other states are systematically biased, or if most such courts are in a cascade, or if their judgments do not bear on any relevant proposition, then their conclusions do not deserve much attention. We hope that these points have general implications for the question of whether an institution, either public or private, might pay respectful attention to the decisions of many other institutions on the same topic.

In his generous and illuminating reply, Nicholas Rosenkranz understands us to have defended the U.S. Supreme Court's occasional practice of consulting the decisions of other high courts. (5) But that was not our goal. Using the CJT, we meant to understand not only why a court might be interested in the decisions of other courts, but also on what assumptions that interest might be unjustified. We noted, for example, that originalists might not be especially concerned about the practices of other courts in other nations, because those practices would not bear on the Constitution's original meaning. (6) It would certainly be possible to read our analysis to explain (a) why state courts should pay attention to the decisions of other state courts, (b) why high courts in India and South Africa should pay attention to the decisions of high courts in other nations, and (c) why the U.S...