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universal jurisdiction, piracy, admiralty, maritime, empirical

Subject Categories

Admiralty | International Law | Jurisdiction | Law


This Essay presents the first systematic empirical study of the incidence of universal jurisdiction prosecutions over an international crime. Using data on the number of piracies committed in a twelve year period (1998-2009) obtained from international agencies and maritime industry groups, we determine the percentage of acts of piracy where nations prosecuted under universal jurisdiction we determine the percentage of these cases where nations exercised UJ. Studies of the worldwide use of UJ over other crimes simply count how often UJ has been exercised, but do not attempt to determine the rate of prosecution.

We find that of all clearly universally punishable piracies, international prosecution occurs in no more than 1.47% of cases. This includes the unprecedented international response to the Somali piracy surge that began in 2008, which accounts for the vast majority of cases. Under normal circumstances (prior to 2008) nations used UJ, a doctrine that arose precisely to deal with piracy, in a negligible fraction of cases (no more than 0.53%, a total of four cases). Another interesting finding is that the nations that apply international criminal law to pirates are quite different from those that use it for other offenses.

Measuring the willingness of nations to exercise universal jurisdiction over human rights offense poses major challenges. Because universal jurisdiction broadly covers torture, war crimes, and other abuses, the number of universally cognizable crimes that go unprosecuted may be quite high. One cannot estimate the universe of possible cases with any precision, and thus cannot determine the frequency of UJ prosecutions in relation to the possible occasions for its use. Piracy, the original and paradigmatic universal jurisdiction crime, provides a unique opportunity to study the implementation of universal jurisdiction in a way that avoids this "denominator problem." Excellent data exists on the actual number of pirate attacks. We examine records of thousands of piracy incidents to determine the number of potential universal jurisdiction cases. The results show that under normal circumstances, nations use universal jurisdiction against a tiny fraction of piracies.