The optimal use of comparative law.

• Author: Dothan, Shai

1. INTRODUCTION

   One of the arguments for the use of comparative law by national courts is that learning from the experience of other nations can improve the quality of the legal decisions made by national courts. This argument has been advanced by Eric Posner and Cass Sunstein (1) using the Condorcet Jury Theorem, which proposes that if a decision is made by a number of independent "jurors," that decision is likely to be a correct decision--and, therefore, a decision worth following. (2) Applied to comparative law, the theorem suggests that if a number of individual states reach the same legal decision, that decision is probably a correct decision and, therefore, a decision worth following.

   Yet there is a problem with this argument, as Posner and Sunstein themselves acknowledge: if states learn from each other's law, their decisions are no longer independent and therefore the theorem's condition of independent "jurors" is no longer met. (3) In fact, in learning from states in other parts of the world, states may fall prey to information cascades in which they harmfully follow each other's lead without analyzing any new information. With that risk in mind, Posner and Sunstein argue that states who want to support the global interest and provide new information on how to improve the law should not imitate others. (4) But while Posner and Sunstein's framework answers the problem of information cascades, it does so at the expense of maximizing the benefits to be gained from comparative law--namely, allowing all states to learn from each other's experiences. (5)

   This paper suggests an alternative framework, one which recovers the benefits of comparative law without risking the development of information cascades. At the heart of this alternative framework is the doctrine of Emerging Consensus, currently used by the European Court of Human Rights ("ECHR"). Under this doctrine, the ECHR examines whether a particular practice has been outlawed by a critical number of states; if so, the ECHR declares that practice to have violated the Convention for the Protection of Human Rights and Fundamental Freedoms ("the Convention"). (6) In other words, the ECHR aggregates the preferences of a wide range of states, each of which has already made an independent decision. The resulting rule allows for the benefits of comparative law--because all states can then adopt the ECHR's rule--without the risk of information cascades, since the rule was based on the "emerging consensus" of states who had already made their decisions independently.

   The remainder of this paper examines the benefits of the Emerging Consensus framework and proposes solutions for the obstacles facing international and regional courts who might wish to apply it--namely, that strategic behavior by states may prevent these courts from reaching good decisions and that these courts may have other motivations, which prevent them from directly applying Emerging Consensus.

   To set up this examination, Part II introduces the argument for the use of comparative law by national courts, noting both the position advanced by Posner and Sunstein as well as the problem of information cascades. Part III then outlines the doctrine of Emerging Consensus and Part IV explains why implementing the doctrine may facilitate better decision-making than simply relying on national courts to use comparative law. Part V suggests doctrinal tools that can ensure the successful use of Emerging Consensus. Part VI addresses the problem of states engaging in strategic behavior that can hinder the effective use of Emerging Consensus and offers some solutions to this problem. Part VII addresses the problem of regional and international courts like the ECHR possibly having motivations other than applying Emerging Consensus correctly. Part VIII concludes by highlighting some of the institutional advantages of international courts over national courts.

2. THE ARGUMENT FOR THE USE OF COMPARATIVE LAW BY NATIONAL COURTS

   1. Posner and Sunstein's Argument

      Posner and Sunstein start from the intuition that states can learn from each other's experience and use the decisions of other nations to improve their own. (7) They use the Jury Theorem, originally invented by the 18th century French philosopher Nicolas de Condorcet, to discipline this intuition. (8) The Jury Theorem is a simple mathematical model that suggests that if a series of jurors decide by majority vote between two answers--one of which is false and the other true--and every juror has a probability of more than 50% to reach the correct result, then the greater the number of jurors, the more likely it is that the decision of the group will be correct. (9) As the size of the group increases, the chances of reaching the correct result approaches 100%. (10)

      Posner and Sunstein synthesize three conditions that are necessary for the practice of comparative law to lead to good results under the Jury Theorem. (11) First, the decisions of the foreign states must sincerely reflect their choices, which are based on private information. (12) Second, the foreign states must be sufficiently similar to make learning from them useful. (13) Third, the foreign states must have decided independently, rather than mimicking the decisions of other states. (14) Posner and Sunstein indicate when these conditions are likely to hold and when they are unlikely to hold. (15) They argue that following the Jury Theorem can often lead to superior results on factual questions, such as which penalty system would prevent crime more effectively, as well as on moral questions, such as which penalty system is morally justified. (16) This paper will focus on the third condition for the applicability of the theory--the requirement that the decisions of different nations must be independent from each other.

   2. The Limitations of National Courts

      Under the framework presented by Posner and Sunstein, national courts should learn from the experiences of other national courts because these other courts made their decisions based on valuable information. (17) But if national courts mimic each other and do not decide independently, their decisions do not reveal any new information as to what is the correct result. (18) Courts that follow each other's decision may form a "cascade." Posner and Sunstein distinguish between two kinds of cascades--reputational and informational. (19) A reputational cascade is formed when decision makers follow each other not because they think this will lead to a better result, but because they are afraid that their reputation will be damaged if they decide differently from the others. (20) An informational cascade is formed when decision makers try to learn from the decisions of others in an attempt to improve their own decisions, but because each decision maker followed other decision makers, no individual decision provides any new information. (21) Reputational cascades may or may not occur depending on states' interests. Informational cascades, however, pose a much greater challenge to Posner and Sunstein's argument, which they clearly acknowledge. Posner and Sunstein's normative claim is that courts should learn from each other in order to reach better results; but if all courts learn from each other, their decisions are not independent and other courts should not learn from them. (22) This framework, therefore, fails to provide a universal rule that can guide courts on how to make good decisions.

      If courts in different states tend to behave differently from each other, Posner and Sunstein's framework can still lead to some valuable normative suggestions. For instance, if some courts are known to decide independently, other courts can learn from these independent choices in order to improve their own decisions. On the other hand, the more courts that follow this suggestion, the lower the quality of information other courts can obtain from looking to comparative law, since fewer courts would decide independently. Therefore, courts who want to help other courts make good decisions should not follow the decisions of other courts--but if all courts were not to follow others, no one will gain the benefits of relying on comparative law. (23) If states clearly diverge in their use of comparative law, a stable equilibrium may theoretically be reached in which some states decide independently and other states learn from their experience. But, if states differ from each other in their propensity to apply comparative law, they may be different in other respects as well. If states are fundamentally different, they should not learn from each other since they are not sufficiently similar to comply with the conditions of the Jury Theorem. (24)

      If national courts do not just follow the final decisions reached by other states, but instead try to evaluate the ultimate reasons that led to those states' decisions, then national courts may be able to discern whether the states' decisions reflect new information or whether they are simply an imitation of the decisions of other states. If the court can expose all the relevant arguments on the subject, however, there is no real need for it to follow the majority of states--the court can simply assess the arguments according to their own merits. The problem is that often the real grounds for the decisions of other courts or states and the information that guided it are hidden or unclear. (25)

      To a certain extent, many states probably exercise some measure of independent discretion when they decide to adopt a legal regime, or at least when they decide to adhere to it after it was adopted. Because informational cascades do not occur immediately, states may have time to test legal regimes independently and render learning from their experience a fruitful exercise. Under these conditions, national courts can gain some informational advantage from comparative law. International courts, however, can sometimes exceed these...