Until recent years, terrorist incidents were viewed by governments as criminal matters to be addressed by civil authorities. The recent emergence of state-sponsored terrorism, however, has presented a level of violence sufficient to impact on fundamental national security interests. When this threshold is reached, individual property interests are secondary to national interests protected by the armed forces. International law and U.S. statutes obligate U.S. naval forces to repress the international crime of piracy. Under most circumstances, piracy as defined in the 1982 Law of the Sea Convention consists of any act of violence against a merchant ship committed by a nongovernmental group while the ship is exercising the right of freedom of navigation. Acts committed in the port or territorial sea of a foreign nation fall primarily under that nation's jurisdiction. U.S. armed forces are responsible for protecting U.S. citizens, property, and flag vessels on the high seas. This article outlines suggested maritime security measures proposed at a workshop sponsored by Woods Hole Oceanographic Institute in April 1985.