Piracy: A Legal Definition

R. Chuck Mason
Legislative Attorney

Pirate attacks in the waters off the Horn of Africa, including those on U.S.-flagged vessels, have brought continued U.S. and international attention to the long-standing problem of piracy in the region. The United States has been an active participant in piracy interdiction and prevention operations focusing on the Horn of Africa region. As part of anti-piracy operations, the U.S. military has detained individuals accused of acts of piracy against U.S.-flagged vessels. In some instances these individuals have been released, others have been transferred to Kenya for criminal prosecution in the Kenyan courts, and some have been brought to the United States for criminal prosecution in the federal courts.

The U.S. Constitution gives Congress the power “To define and punish Piracies and Felonies committed on the high seas, and Offenses against the Law of Nations.” Since 1819, U.S. law has defined piracy not as a specific act, but rather “as defined by the law of nations.” The U.S. Supreme Court, in United States v. Palmer and United States v. Smith, has upheld Congress’s power to define piracy in terms of the law of nations. The Court has found that piracy, under the law of nations, requires a robbery at sea. In addition to U.S. law, contemporary international agreements, including the Convention on the High Seas, the Convention for the Suppression of Unlawful Acts Against the Safety of Maritime Navigation (SUA Convention), and the United Nations Convention on the Law of the Sea (UNCLOS), address piracy. The United States is party to the first two agreements, and the third (UNCLOS) is generally accepted as reflecting customary international law.

The United States Navy, after thwarting two separate alleged acts of piracy, transferred suspected pirates to Norfolk, VA, for criminal trials in the U.S. District Court for the Eastern District of VA, on charges of piracy. One of the trials, United States v. Hasan, ended with the defendants found guilty on numerous charges, including piracy. The other case, United States v. Said, is on appeal based on a court ruling dismissing the charge of piracy. A common issue between the two cases, and yet the greatest distinction, is how the two trial courts interpreted the definition of piracy under 18 U.S.C. § 1651.

The Said court stated that the act of piracy, as defined by the law of nations, requires a robbery on the high seas. Thus, it appears that absent an actual robbery at sea, individuals may not be found guilty of the act of piracy under 18 U.S.C. § 1651, but may be tried for other offenses, including the offenses of attack to plunder a vessel, or committing violence against a person on a vessel. In Hasan, the trial court ruled that the act of piracy, as defined by the law of nations, is reflected by Article 110 of UNCLOS and thus does not require an actual robbery at sea to be convicted of piracy.

The divergent U.S. district court rulings may create uncertainty in how the offense of piracy is defined. Congress may provide guidance to the courts by clarifying the definition of piracy under 18 U.S.C. § 1651. However, in the absence of legislative clarification, the courts may arrive at differing interpretations.


Date of Report: December 13, 2010
Number of Pages: 13
Order Number: R41455
Price: $29.95

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