Customary International Law from The Point of View of Game Theory

INTRODUCTION

Customary international law is one of two primary forms of international law, the other being the treaty.[1] Customary international law refers to obligations arising from established international practices, as against to obligations arising from formal written conventions and treaties. Customary international law is the result of a general and consistent practice of states that follow a legal obligation approach.

Along with general principles of law and treaties, the custom is taken into account by the International Court of Justice, jurists, the United Nations, and its member states to be among the first sources of international law. In 1950, the International Law Commission listed the subsequent references as proof of customary international law: treaties, decisions of national and foreign courts, national rules, opinions of national legal experts, diplomatic correspondence and practice of international bodies.[2]

Professors Jack Goldsmith and Eric Posner have questioned the positivist account of customary international law using game theoretical concepts.[3] Their writings join other early attempts to use the theory of game to international law sources. In their view, game-theoretic principles suggest that customary norms are in fact the result of self-interested states acting in various strategic situations.

RECOGNITION OF CUSTOMARY INTERNATIONAL LAW

Article 38(1) (b) the Statute of the International Court of Justice describes customary international law as “a general practice recognized as law.” This is often generally determined through two factors: the overall practice of states and what states have accepted as law (opinio juris sive necessitatis). In international law, “opinio juris” is the subjective element used to judge whether the practice of a state is due to a belief that it’s legally obliged to try a specific act. When opinio juris exists and is according to nearly all state practice, customary international law emerges.

There are several sorts of customary international laws recognized by states. Some customary international laws rise to the extent of jus cogens[4] by accepting them as inviolable rights by the international community, while a small group of states may simply follow other customary international law. States are typically bound by customary international law no matter whether the states have codified these laws domestically or through treaties.

GAME THEORY OF CUSTOMARY INTERNATIONAL LAW

Professors Goldsmith and Posner suggest that new insight is often gained by identifying those situations during which behavioral regularities among states arise. In their view rather than a set of rules established by a general and consistent practice followed out of a way of a legal obligation, customary international law simply refers to behavioral regularities that arise from self-interested interactions between states in different strategic contexts.

There are four basic situations that give rise to such regularities viz. coincidence, coercion, cooperation, and coordination.

1. Coincidence:

Coincidence of interest occurs’ where states engage in behavioral regularities simply because each person obtains private advantages from a particular action (which happens to be an analogous action taken by the opposite state) regardless of the opposite action. Professors Goldsmith and Posner posit a situation in which each of two belligerent states that patrol an equivalent body of water can choose from attacking or ignoring commercial fishing vessels of the opposite state. Under certain conditions, it’s simply more beneficial for every state, acting without reference to the opposite, to ignore the opposite state’s fishing boats than it is to attack them.

2. Coercion:

Coercion happens when “one state, or a coalition of states with convergent interests, forces other states to interact in actions that serve the interest of the primary state or states. A strong state could threaten to destroy a weaker state’s navy if it attacks the stronger state’s fishing boats. The stronger state could do that if the prices of completing the threat are relatively low. The weaker state, realizing that its payoff for attacking the stronger state’s boats is extremely low, won’t do so. If the stronger state features a better use for its navy, it too will refrain from attacking the weaker state’s boats. Again, regularity in behavior is explained not by a general rule but by states responding rationally to a given strategic situation.

3. Cooperation:

Over repeated interactions, though, states realize that it’s more beneficial to cooperate so long as the other doesn’t defect. However, several conditions must be met.

  1. Both parties must care about the longer-term i.e. they must both be willing to defer a present payoff for future gains.
  2. The states must believe that they are going to still encounter one another for the foreseeable future.

Finally, the payoffs for defection must not be too high relative to the payoffs for cooperation. Due to these conditions, Professors Goldsmith and Posner believe that behavioral regularity among states through cooperation is less likely to arise than through coincidence of interest or coercion. Nevertheless, real cooperation between states happens when these conditions exist.

4. Coordination:

Coordination between states can arise when “each state’s best move depends on the move of the opposite state.” The matter, however, is that there must be some way of knowing or communicating beforehand what each state will do to form coordination possible; otherwise, the states must choose to support some guess on what the opposite will do.

ANALYSIS OF GAME THEORY

Since, in Professors Goldsmith and Posner’s view, most behavioral regularity among states are often explained as self-interested responses in one or more of those four sorts of games, it’s not necessary to assert a universal customary norm that explains such behavior. Their theory suggests that much apparently cooperative universal behavioral regularity is illusory.

Professors Goldsmith and Posner argue that in no instances does a state act out of a way of legal obligation. It acts to serve its own national interest. This self-interest leads to shifts, sometimes rapid, in customary norms. Customary norms form and alter when either the principles of the game or its payoffs change. In the case of coincidence of interest, such interests change when the environment changes. In the case of coercion, change occurs when a state is not any longer more powerful than the opposite. In the case of coordination games, customary norms can arise and alter through trial and error.

As support for their theory, Professors Goldsmith and Posner examine specific areas where customary international law is assumed to be robust: neutrality, exemption, maritime jurisdiction, and the protection of coastal fishing vessels. In each case, they argue that it is better to clarify the record of actual state actions by self-interested reactions to particular strategic circumstances than by exogenous customary international norms.

CONCLUSION

There could also be two major conclusions drawn from this analysis. First, states do not comply with customary international law out of a way of legal obligation as they act out of their rational self-interest in their interactions with other states. Second, they’re skeptical that regularities in behavior among states that constitute a general and consistent practice exist. Perhaps game theory’s greatest potential for contributing to international law is to supply a rigorous means of describing and articulating important aspects of state interaction and cooperation.[5]

The hope is that fully developed game-theoretic models will help states design law that makes or enhances the conditions for cooperation if such cooperation is desirable. Such models would help the international community understand better why some problems are more intractable than others.[6] States could then decide how institutional and diplomatic resources should be allocated to deal with such issues. Game theory also could assist in evaluating existing law and suggesting improvements thereto to law. Lastly, the game theory could help clarify the conditions under which breaches of the law are likely.[7]

[1] Eric Posner & Jack L. Goldsmith, A Theory of Customary International Law, 66 University of Chicago Law Review 1113 (1999) (Visited on June 16, 2020)

< https://chicagounbound.uchicago.edu/cgi/viewcontent.cgi?article=2767&context=journal_articles>

[2] Evidence of State practice, archive from Wayback Machine

[3] Supra Note 1

[4] Jus Cogens, Latin term used for ‘compelling law’

[5] Jon Hovi, Games, Threats & Treaties: Understanding Commitments in International Relations (1998)

[6] Hugh Ward, Game Theory and the Politics of Global Warming: The State of Play and Beyond, 44 POL. STUD 850, 853-62 (1996)

[7] Kenneth W. Abbott, “Trust but Verify”: The Production of Information in Arms Control Treaties and Other International Agreements, 26 CORNELL INT’L L.J. I (1993)

This Article is Authored by Deeksha Shrivastava, 2nd year, BA LLB Student at FIMT College, Guru Gobind Singh Indraprastha University, New Delhi.

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