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Behavioral Aspects of the International Law of Global Public Goods and Common Pool Resources

Published online by Cambridge University Press:  16 March 2018

Anne van Aaken
Anne van Aaken*
Affiliation:
Professor of Law and Economics, Legal Theory, Public International Law and European Law, University of St. Gallen, Switzerland.
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Abstract

Collective action problems with public good characteristics such as climate change have important implications for international law. This note argues that behavioral insights from laboratory experiments, in which individuals engage in public goods games, can contribute to our understanding of how best to optimize the design of international legal regimes dealing with global public goods and common pool resources. Behavioral economics, to the extent it supplements or displaces rational-choice models in institutional design, may enable deeper and more sustained forms of international cooperation.

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Type
Notes and Comments
Information
American Journal of International Law , Volume 112 , Issue 1 , January 2018 , pp. 67 - 79
Copyright
Copyright © 2018 by The American Society of International Law 

Introduction

Climate change and overfishing are quintessential problems calling for international cooperation. They rank among international law's great challenges not only because of their global significance, but also because the collective action problems they pose are stark and difficult. The predominant paradigm for addressing such cooperation issues is rationalist.Footnote 1 Many rationalist scholars dealing with global collective action problems use game theory. This is particularly the case with respect to efforts to understand the extent of state compliance, where much of the scholarly debates have been dominated by rival advocates of managerial as opposed to enforcement-oriented approaches.Footnote 2 Analyses of the problems posed by non-compliance typically focus on the behavior of states as single entities. It is routine to assume that states strategically pursue their own individual self-interests.Footnote 3 The main variant to the focus on individual decision-makers (decision theory) are those that look to strategic interactions (game theory). Neither is particularly optimistic about the prospect for interstate cooperation. Indeed, rationalists’ pessimism on the prospects of cooperation vis-à-vis Common Pool Resources (CPR) and Global Public Goods (GPG) is aptly summarized by two iconic phrases: “tragedy of the commons”Footnote 4 and “logic of collective action.”Footnote 5 GPG and CPR are sometimes framed as prisoner's dilemmas, where (in a non-repeated game) two completely “rational” individuals might not cooperate, even if aggregate welfare would be maximized by cooperating. Rationalists accept that in iterative scenarios, cooperative outcomes may vary, but, despite increased refinements in rationalist approaches, such scholars still miss important factors that may contribute to cooperation.Footnote 6 Rationalism does not offer coherent hypotheses for when actors will achieve more or less socially desirable outcomes.Footnote 7 Because of anticipated second-order enforcement problems, free-riding, and cheap talk, rationalists expect that promises are likely to be either unenforceable or at best underenforced.Footnote 8 Indeed, enforcement, if costly to the punisher, is seen as another prisoner's dilemma since all actors prefer to free-ride on the enforcement measures by other players.Footnote 9 Moreover, agreements with no or limited enforcement mechanisms will be expected not to have any impact on behavior.Footnote 10 This pessimistic account underpins an inference that stable and effective cooperation for GPGs at the big scale needed to resolve the underlying problems—that is, to cooperate sufficiently to address climate change—is likely to prove impossible.

Yet pessimistic models do not completely square with the available empirical evidence. Notably, “predictions based on [rational choice] model[s] are not supported in field research or in laboratory experiments in which individuals face a public good [PG] or CPR problem and are able to communicate, sanction one another, or make new rules.”Footnote 11 Moreover, policies that seek to respond to the theoretical insight of Hardin's Tragedy of the Commons, such as efforts to privatize or to encourage cooperation through the allocation of private titles to property, have failed to adequately address—and may have even exacerbated—the very problems they were intended to ameliorate.Footnote 12 Meanwhile, at the level of theory, the rational choice paradigm has been thoroughly challenged since the 1970s by psychological and experimental economics research.Footnote 13 Regrettably, despite the widespread influence of the “behavioral revolution” in economics, behavioral insights have seldom been applied to the study of GPGs and CPRs.Footnote 14 In 1999, Elinor Ostrom lamented: “We have not yet developed a behavioral theory of collective action based on models of the individual consistent with empirical evidence about how individuals make decisions in social-dilemma situations.”Footnote 15 This note begins to address this gap. It considers the prospects for enduring cooperation on collective action problems as such, leaving to one side general compliance theories, while addressing questions such as the likely impact of U.S. withdrawal on the Paris Agreement. This does not require a rejection of rationalist approaches. Underlying incentive structures, the roles of strategic interests, and numerous other rationalist foundations, are, to be sure, of fundamental importance. But the analysis of international law in the context of collective action problems can be enriched by applying insights into how people really behave.

While rationalist and constructivist approaches are grounded in certain assumptions about individual or state behavior, behavioral insights derived from psychological and economic experiments can supply evidence for those assumptions—or undermine them by supplying counterintuitive results.Footnote 16 The value of such experiments lies in offering evidence of real world behavior, which can either support, undermine, or supplement the underlying theoretical frameworks behind legal design. Empirical research based on experiments may also help to bridge rationalist and constructivist approaches to international law by providing support for long held constructivist assumptions about, for example, how people react to fairness considerations.Footnote 17

This note first considers some objections to the use of psychological insights in international relations. Second, it describes public good experiments, before turning to the factors which help to produce cooperation in prisoner's dilemma or other situations.

I. Why Apply Experimental Insights to States?

Applying experimental psychology to states is not as farfetched as it may seem. While a complete defense is not possible here, three considerations militate in favor of drawing on behavioral psychology's insights.

First, other fields studying state behavior already draw on behavioral findings. For example, the field of international relations has long used insights from political psychology.Footnote 18 Recently, international relations scholars have turned to behavioralism in particular.Footnote 19 Moreover, insights from behavioral economics have been applied to law concerning corporate actors.

Second, purely rationalist theories of state action reflect the outdated assumptions of the pre-behavioral revolution era.Footnote 20 Given the current state of knowledge, there is a strong disconnect between the behavioral assumptions for states on the one hand and behavioral insights for individuals on the other hand. Rather than insisting that behavioralists justify extrapolating from individuals to states, it is precisely this disconnect that needs justification.

Third, old-school rationalist accounts presume a unitary state, despite the growing evidence that states are not opaque billiard balls interacting with one another but each consist of a multiplicity of relevant “liberal” actors.Footnote 21 GPGs and CPRs in particular are increasingly seen as requiring multi-actor, multi-sector, and multi-level analysis.Footnote 22 A striking articulation of this view is Anne-Marie Slaughter's metaphor of international law as a “Lego World”Footnote 23 in which different actors can be looked at separately. To take a concrete example: the domestic response to President Trump's withdrawal from the Paris Agreement has raised the prospect that cities, states, and businesses will become the key actors in hitting the relevant targets. The less the relevant unit of analysis resembles a unitary sovereign, the more behavioral insights seem applicable.

These arguments do not, to be sure, amount to a complete defense. There are legitimate concerns about external validity of the experiments on which the behavioral theories are based. Moreover, lack of certainty about the relevant unit of analysis in dealing with international law cuts both ways, in that it constitutes an additional source of uncertainty in translating results across contexts.Footnote 24 But these three facts suggest that it is at least plausible as an initial matter to extrapolate from individual studies to the analysis of states—or at least that it is reasonable to consider the relevance to international law of some of the types of behavioral experiments identified below.

II. Public Good Experiments

Experiments can be used to observe peoples’ social preferences and cognition under controlled conditions. They may be conducted in the field or in laboratory settings, and may assess individual or group behavior. Many experiments show deviations from the rational choice model such as cognitive biases and heuristics, including loss aversion and the endowment effect. Such insights, imported into behavioral contract theory, can help inform treaty design.Footnote 25 This part focuses solely on public good games which address how cooperation emerges and can be sustained.Footnote 26 Experiments on social preferences use game theory, including, in particular, by deploying variations on the ultimatum game. In this experiment, the proposer makes an offer of how to share a fixed amount, which the recipient can accept or reject. If the recipient rejects, both get nothing. In a homo economicus model, a proposer would offer the smallest monetary unit, and the recipient would accept it. Yet experiments do not obtain this result. Typically, this is attributed to fairness concerns.Footnote 27 The dictator game is comparable to the “ultimatum” game, but in this instance the recipient cannot reject the result and therefore there is no sanction for failing to share. In this case as well participants consistently share the endowment.Footnote 28 Across game types and individual studies, subjects consistently behave in a manner not predicted by rationalist assumptions of narrow self-interest—for example, by dividing resources in a manner that reflects fairness concerns rather than merely maximizing individual gain.

Even more relevant are “public good” games, which mimic the incentive structure of GPGs and CPRs. Public good games are used to explore whether individuals contribute to public goods where rational choice would expect free-riding. A typical public good game is designed as follows: n subjects are each given an initial endowment of money. They may contribute some, all, or none of their endowment to the public good. The contribution to the public good is multiplied by some factor k, where k is greater than one but less than n. This enlarged pot is then shared equally between all group members. Thus, a subject s who contributes one unit to the public good thus benefits the group as a whole, since k is greater than one, but s loses out herself, since k÷n is less than one.

The best outcome for group welfare would be if each subject contributed her full endowment to the public good. However, each subject has an incentive to free-ride on everyone else's contributions. In this scenario, standard economic theory predicts that nothing will be contributed to the public good. This prediction, known as the “strong free-rider” hypothesis, is challenged by the experimental results; in experiments, real human beings are not strong free-riders, they do in fact contribute to the public good and punish others who do not, even at some cost to themselves.

Repeated findings that individuals systematically engage in collective action to provide local PG or manage CPRs without an external authority enforcerFootnote 29 have led some to label such outcomes “better than rational.”Footnote 30 Such outcomes occur where “reciprocity, reputation, and trust can help to overcome the strong temptations of short-run self-interest.”Footnote 31 These experiments suggest that rationalist theories may be faulted for neglecting: (1) reciprocity strictu sensu; (2) the distinction between (perceived) fair and unfair sanctions; (3) altruism, spitefulness, and preferences for equality; (4) the role of trust and communication; (5) the intentions of the other players; and (6) the “type” of actor. Further, it has been suggested that these factors are “probably relevant in all domains in which voluntary compliance matters.”Footnote 32 Insofar as such insights can be applied when the unit of analysis is the state, the implications for environmental treaties—indeed, for any treaty characterized by CPRs, GPGs, or voluntary compliance—are clear.

III. Factors Helping to Produce Enduring Cooperation

Careful attention to the factors that lead to cooperation in behavioral experiments is needed if these are to be useful to treaty designers. These factors—(1) internalized norms of cooperation, sustained by emotions such as guilt and shame and underlying moral norms such as fairness concerns; (2) concern for the specific behavior of others, such as reciprocity; (3) communication and trust-building; and (4) sanctions imposed on non-cooperators—are elaborated in the sections that follow.

A. Framing and Moral Judgments

A framing effect exists “when different ways of describing the same choice problem change the choices that people make, even though the underlying information and choice options remain essentially the same.”Footnote 33 Framing effects violate the rationalist axiom of “descriptive invariance.”Footnote 34 Many experiments explore those effects,Footnote 35 including in public good games.Footnote 36 The mechanism at work is that frames influence beliefs, and beliefs in turn influence behavior.Footnote 37 Specific examples abound: framing ultimatum games as a product of resource scarcity generates higher offers and fewer rejections;Footnote 38 framing negotiations as taking place in an international rather than a business context triggers more cooperative behavior;Footnote 39 and supposedly framing the prisoner's dilemma as a trust game can increase cooperation.Footnote 40

Framing can also activate moral sentiments, allowing behavioral game theory to expand on rationalist game theory “by adding emotion[s], mistakes, limited foresight,” and learning.Footnote 41 As discussed in Section II, people are willing to enforce moral norms even at economic cost to themselves.Footnote 42 Anger and guilt are especially pertinent in the context of social cooperationFootnote 43 because free-riding is perceived to be morally blameworthy, triggering anger in the cooperator and guilt in the free-rider.Footnote 44 Recognizing the role of these emotions permits expanding the range of potential sanctions to include not just traditional external sanctions, but also “internal punishment” (i.e. guilt or shame) that provides an intrinsic reason for action.Footnote 45 Cooperation can thus be supported to the extent that people think cooperating is morally the right thing to do and feel guilt at the prospect of breaking the social contract. Legal designers can take advantage of these insights by using framing to express a view on what is “the right thing to do.”Footnote 46

An additional mechanism that merits mention is inequality aversion, which is a conditional form of altruism.Footnote 47 It describes a situation in which an actor's utility increases if the allocation of material payoffs becomes more equitable. Given that “equitable” varies depending on the baseline for evaluation, legal designs can use framing to shape the perception of equity, which in turn will influence actors displaying inequality aversion.

B. Reciprocity and Types of Actors

Despite definitional ambiguities, reciprocity is recognized as being foundational to modern society and international order.Footnote 48 A simple version of reciprocity is the Golden Rule—do unto others as you would have them do unto you. Reciprocity can be learned. Specifically, humans can learn reciprocity norms so as to enhance returns from collective action.Footnote 49 Behavioral economics points to different potential motivations for reciprocal behavior, with different implications for international law. Weak reciprocity, which maps onto what Keohane has called “specific” reciprocity,Footnote 50 emphasizes solely self-interested behavior in which each cooperative or retaliatory act is motivated by future benefits. Strong reciprocity, corresponding roughly to Keohane's “diffuse” reciprocity,Footnote 51 reflects a desire for balance driven by comparison and matching, and is related to equality and fairness concerns.Footnote 52 Many people are strong negative reciprocators with punitive sentiments for wrongdoing, that is, they react strongly to free-riders even if such a reaction is very costly to themselves.Footnote 53 Whereas rationalists do not expect costly punishment by others in public good games, behavioral insights show punishment by other players takes place and thus fosters cooperation.

Ostrom, Burger, Field, Norgaard, and Policansky characterize different types of actors in CPR constellations, similar to those found in the experiments:

(u)sers of a CPR include (i) those who always behave in a narrow, self-interested way and never cooperate in dilemma situations (free-riders); (ii) those who are unwilling to cooperate with others unless assured that they will not be exploited by free-riders; (iii) those who are willing to initiate reciprocal cooperation in the hopes that others will return their trust; and (iv) perhaps a few genuine altruists who always try to achieve higher returns for a group.Footnote 54

Mitchell has a similar categorization for climate change actors characterizing states: “committed, contingent, resistant and intransigent.”Footnote 55 If non-contribution is perceived as intentional as well as unfair and “unkind,” stronger reactions are to be expected.Footnote 56 The expectation is that if there are enough players “in” and there is a reasonable expectation that other states will comply, the majority of actors, so-called conditional cooperators that are willing to invest trust, will indeed cooperate, even if there are some resistant players.

Can behavioral economics tell us anything about the likely consequences of the United States’ withdrawal from the Paris Agreement?Footnote 57 Does the withdrawal of one important country matter for successful cooperation on climate change or will other countries stand firm(er) in their commitment? If other countries continue to reaffirm their commitment to the Paris Agreement, the one resistant country, even if big, should not matter for continuous cooperation. In the wake of the Trump administration's announcement, China and the EU immediately reaffirmed their commitment to the Agreement and even deepened their cooperation.Footnote 58 This could create enough confidence and trust for other conditional cooperators, thereby preventing the unravelling of the Agreement. Behavioral economics suggests that credible reassurances by all remaining partners of each other's commitment is crucial—and not, as some rationalists would maintain, merely “cheap talk.”

C. Communication and Trust

Rationalists, like Goldsmith and Posner, describe much of international law as weak “cheap talk,” that is, costless, non-binding, pre-play communication.Footnote 59 In experiments, the “cheap talk” hypothesis has been shown to be wrong: communication helps actors to achieve efficient results.Footnote 60 Face-to-face communication and knowing the other participants with whom one is interacting improves cooperative outcomes.Footnote 61 As Ostrom contends, “the relationships among trust, conditional commitments, and a reputation for being trustworthy are key links in a second-generation theory of boundedly rational and moral behavior.”Footnote 62 It is assumed that communication facilitates cooperation because it: (1) transfers information from those who figure out an optimal strategy to those who cannot determine what strategy is optimal; (2) encourages the exchange of mutual commitments; (3) increases trust and thereby affects expectations of others’ behavior; (4) adds additional value to the subjective payoff structure; (5) reinforces prior normative values; and (6) develops a group identity.Footnote 63 Additional factors relevant to trust models are group identity, social capital, and perceived intention.Footnote 64

D. Sanctions

Despite the influence of other mechanisms on (human or state) behavior, sanctions remain necessary.Footnote 65 There are reasons for skepticism about the efficacy of sanctions, if one takes a traditional, narrow view of what sanctions are. As Abram and Antonia Chayes pointed out some time ago, authority to impose economic or military sanctions are “rarely granted by treaty, rarely used when granted, and likely to be ineffective when used.”Footnote 66 However, experiments show that other forms of sanctioning can be effective. Not all sanctions are alike, and sanction design should reflect behavioral insights. In particular, as discussed below, sanctions can be more or less fair, more or less centralized, may consist of forms of outcasting, and be more symbolic than real.

1. Perceived fairness of sanctions

Sanctions perceived as selfish or greedy destroy altruistic cooperation; however, fair sanctions leave altruistic cooperation intact.Footnote 67 Importantly, sanctioning free-riders in PG games is perceived as fair.Footnote 68 Welfare is maximized where a single player—either a third party or a designated group member—has sanctioning authority.Footnote 69 Under such conditions, the third party is most likely to punish a defector if other players cooperated, reflecting internalized fairness considerations in sanctioning decisions.Footnote 70 A perception of fairness has been shown to be important for maintaining collective action. Treaty bodies in the climate change regime provide an illustration. Several of them can be seen as being third-party punishers, even if they do not resemble the archetypal neutral third-party in law: the court. For example, Article 8.3 of the Kyoto Protocol tasks expert review teams with identifying questions of implementation of commitments, although not with determining compliance.Footnote 71

The Kyoto Protocol established the most elaborate compliance regime ever developed under an international environmental agreement.Footnote 72 Its unique Compliance Committee consists of the Facilitative and the Enforcement Branches. Monitoring, reporting, review, and verification are at the forefront of its compliance facilitation mechanisms. When non-compliance appears likely, the Facilitative Branch can take steps including advice, financial and technical assistance, and capacity building.Footnote 73 The Enforcement Branch, which has jurisdiction over Annex I countries, can indicate “consequences” for non-compliance. Those differ depending on the underlying commitment. In cases of non-compliance with inventory or reporting commitments, consequences will consist in a declaration of non-compliance and in the requirement that the party concerned prepare a “compliance action plan” (Procedures and Mechanisms, XV.1). If a party has not met one or more of the eligibility requirements for the Kyoto mechanisms, the consequence will be suspension of the party from participation in the mechanisms (Procedures and Mechanisms, XV.4).Footnote 74 The goal is to provide for “the restoration of compliance to ensure environmental integrity” and “for an incentive to comply.”Footnote 75 The Kyoto Protocol “Procedures and Mechanisms on Compliance” contain several safeguards to ensure due process and thus ensure the sanctions are viewed as fair. The decision structure is complicated and its description would exceed the space limit here, but, for example, under the Procedures and Mechanisms (XI.4), an appeal is permitted to the meeting of the parties if the affected party “believes it has been denied due process.”Footnote 76 It has been suggested that this whole structure and its due process elements had an impact on full compliance by parties in the first commitment period (without any recourse to traditional sanctions).Footnote 77

2. Outcasting: Public and club goods

Outcasting—defined as the use of techniques to deny non-compliant states the benefits of social cooperation and membership or use of markets—is an important but neglected enforcement mechanism in international legal theory.Footnote 78 It is often used in international law, especially with regard to treaties dealing with GPGs and CPRs. The use of exclusion as punishment for non-cooperation converts public goods to excludable non-rivalrous goods in terms of consumption—that is, club goods.Footnote 79 This technique is used, for example, in Article 4 of the Montreal Protocol which bans the import of the controlled substances listed in the Annexes from non-parties.Footnote 80 Exclusionary mechanisms have been extended to markets and non-state actors in other GPGs, making appearances, for example, in the Financial Action Task Force (FATF) and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).Footnote 81 Excluding defectors from club goods is a cheap and impactful sanctioning device.Footnote 82 The conditions under which such devices are effective are twofold: (1) where there is some economy of scale associated with the larger group; and (2) where bad behavior can be detected and used as the basis of an exclusion sanction. Where exclusion is reversible, it is possible to achieve even larger contributions to the PG.Footnote 83 In addition to serving as a sanction, shifting from a pure PG to a club good also expresses one's affiliation to one's social group via positive in-group reciprocity.Footnote 84

3. Symbolic sanctioning

Finally, even purely symbolic sanctioning—such as disapproving statements or oral condemnations—can enlist cooperation. Given the widespread use of this in international regimes, this is good news for international lawyers. Experiments show that people are sensitive to the evaluation of others, including in part as a response to guilt and shame triggers.Footnote 85 Symbolic sanctioning can be effective even where there is no prospect of a reduced material payoff.

IV. Conclusion

Theories of international cooperation can benefit from the use of behavioral insights. Consideration of such experiments can eventually lead to theories of international cooperation that are explicitly based on empirically validated views about group and individual behaviors. Those insights paint a more optimistic picture of the possibility of solving international social dilemmas than rationalist approaches do. Of course, material interests and strategic interaction remain important. But behavioralism has been underappreciated even though its experiments yield more factors to consider—more tools in the toolbox—that may enable sustained cooperation.

Behavioral insights also have the potential to bridge the gap between rationalist and constructivist theories of international law. Behavioral economics has a rationalist starting point, but hints at ideas long advanced by constructivist scholars, thereby opening opportunities for dialogue.Footnote 86 Constructivists have long questioned the rationalist account of preference formation, proposing an alternative model that emphasizes the social nature of preferences.Footnote 87 They have also long recognized the significance of framingFootnote 88 and emphasized communication and trust-building institutions, all while presuming the effectiveness of symbolic and fair sanctioning by independent third parties. Behavioral research may confirm at least some tenets of the constructivist school—while providing empirical validation that can itself refine their analytic insights. At the same time, experimental research may refine rationalists’ emphasis on the roles of strong reciprocity and conditional cooperation.

Experimental research is still relatively young. The design of many behavioral experiments is ill-suited to answer with precision important open questions in international law. More research is needed, including more tailor-made experiments. Despite this, it has generated many insights which have the potential to enrich our understanding of GPGs and CPRs. Given the pressing and difficult nature of the issues, it would be remiss to leave any promising tools unused in the toolkit for cooperation.

References

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43 Gächter, Simon, Human Pro-social Motivation and the Maintenance of Social Order , in Handbook on Behavioral Economics and the Law 37 (Zamir, Eyal and Teichman, Doron eds., 2014)Google Scholar.

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49 Gintis, Herbert, Strong Reciprocity and Human Sociality , 206 J. Theoretical Bio. 169 (2000)Google Scholar; Bowles & Gintis, supra note 48.

50 Keohane, supra note 48, at 4 (defining specific reciprocity as “situations in which specified partners exchange items of equivalent value in a strictly delimited sequence”).

51 Id. (defining diffuse reciprocity as “conforming to generally accepted standards of behavior”).

52 See, e.g., Gintis, supra note 49; Bowles & Gintis, supra note 48, at 20.

53 Surveyed in Gächter, Simon & Herrmann, Benedikt, Reciprocity, Culture, and Human Cooperation: Previous Insights and a New Cross-Cultural Experiment , 364 Phil. Transactions Royal Soc’y B – Biological Sci. 791 (2009)Google Scholar.

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58 Daniel Boffey & Arthur Neslen, China and EU Strengthen Promise to Paris Deal with US Poised to Step Away, Guardian (June 1, 2017), at https:// www.theguardian.com/environment/2017/may/31/china-eu-climate-lead-paris-agreement.

59 See, e.g., Goldsmith & Posner, supra note 8, at 175–80.

60 See Charness, Gary, Self-Serving Cheap Talk: A Test Of Aumann's Conjecture , 33 Games & Econ. Behav. 177 (2000)Google Scholar.

61 Ostrom, supra note 7, at 7; Camerer, supra note 41, at 76 with further references.

62 Ostrom, supra note 7, at 7.

63 Id.

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66 See Chayes, Abram & Chayes, Antonia Handler, The New Sovereignty: Compliance with International Regulatory Agreements 32–33 (1998)Google Scholar. See also Downs, Rocke & Barsoom, supra note 3.

67 Bowles & Gintis, supra note 48, at 28.

68 This experimental research has also been validated by field research, most prominently by Tyler, Tom R., Why People Obey the Law (1990)Google Scholar.

69 O'Gorman, Rick, Henrich, Joseph & Vugt, Mark Van, Constraining Free Riding in Public Goods Games: Designated Solitary Punishers Can Sustain Human Cooperation , 276 Proc. Royal Soc’y B – Biological Sci. 323 (2009)Google Scholar.

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71 Brunnée, supra note 2, at 272 (“This mandate is designed to preserve the technical and factual focus of expert review and to clearly separate it from potentially sensitive and politicized compliance issues.”). See also United Nations Framework Convention on Climate Change, May 9, 1992, 1771 UNTS 107; Marrakesh Accords, Jan. 21, 2002, UN Doc. FCCC/CP/2001/13/Adds. 1–4.

72 Brunnée, supra note 2, at 256.

73 Mitchell, supra note 55, at 73 et seq.

74 For further examples, see Brunnée, supra note 2, at 274.

75 Decision 27/CMP.1, Procedures and Mechanisms Relating to Compliance Under the Kyoto Protocol, at V.6, UN Doc. FCCC/KP/CMP/2005/8/Add.3.

76 Jon Hovi, Olav Stokke & Geir Ulfstein, Introduction and Main Findings, in Implementing the Climate Regime: International Compliance, supra note 55, at 3.

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79 Id. For the definition of club goods, see Buchanan, James M., An Economic Theory of Clubs , 32 Economica 1 (1965)Google Scholar.

80 Montreal Protocol on Substances that Deplete the Ozone Layer, Sept. 16, 1987, 1522 UNTS 29.

81 Convention on International Trade in Endangered Species of Wild Fauna and Flora, Mar. 3, 1973, 993 UNTS 243. Articles III, IV, and V regulate the trade in endangered species differently depending on the how endangered the species is. Without import and export certificates, no trade can take place.

82 For details, see van Aaken, Anne, Effectuating Public International Law Through Market Mechanisms , 165 J. Institutional & Theoretical Econ. 33 (2009)CrossRefGoogle Scholar, and van Aaken, Anne, Trust, Verify or Incentivize? Effectuating Public International Law Regulating Public Goods Through Market Mechanisms , 104 ASIL Proc. 153 (2011)Google Scholar. On the efficacy of this device, see Gary Charness & Chun-Lei Yang, Public Goods Provision with Voting for Exclusion, Exit, and Mergers: An Experiment, at 21 (Working Paper, 2010), available at https://www.researchgate.net/publication/228687877_Public_Goods_Provision_with_Voting_for_Exclusion_Exit_and_Mergers_An_Experiment; Cinyabuguma, Matthias, Page, Talbot & Putterman, Louis, Cooperation Under the Threat of Expulsion in a Public Goods Experiment , 89 J. Pub. Econ. 1421 (2005)Google Scholar (finding “that contributions rose to nearly 100% of endowments with significantly higher efficiency compared with a no-expulsion baseline.” Expulsions were strictly of the lowest contributors, and there was an exceptionally strong fall-off in contributions in the last period, when the expulsion threat was unavailable.).

83 Charness & Yang, supra note 82.

84 Chakravarty, Surajeet Chakravarty & Fonseca, Miguel A., Discrimination via Exclusion: An Experiment on Group Identity and Club Goods , 19 J. Pub. Econ. Theory 244 (2017)Google Scholar (finding that club goods allow subjects to display their preferences for interaction with their in-group members, as well as positive in-group reciprocity).

85 Bowles & Gintis, supra note 48, at 29 et seq.

86 As here, Hafner-Burton, Haggard, Lake & Victor, supra note 14, at S3.

87 For a comparison between rationalist and constructivist approaches, see Fearon, James & Wendt, Alexander, Rationalism v. Constructivism: A Skeptical View , in Handbook of International Relations (Carlsnaes, Walter, Risse, Thomas & Simmons, Beth A. eds., 2002)Google Scholar.

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