Since the September 11, 2001 terrorist attacks on the United States, there has been increasing attention given to the nexus between terrorism, proliferation of weapons of mass destruction (WMD), and the security of the maritime transport sector. The September 11 attacks not only exposed the loopholes in airport and airplane security, but also alerted the U.S. and the world to the gaping security vulnerabilities in other transport sectors. The very nature of international shipping has made it far more difficult to protect and thereby render it open to abuses. International maritime vessels are often owned by companies in one country, registered in another, manned by crew from several other nations, and call at ports around the world. Ships transport more than 80 percent of the world’s trade by volume, from high-value goods such as oil and liquefied natural gas to everyday commodities. Most goods are transported on large cargo ships in containers; in fact more than 200 million containers are transported across the globe each year. The U.S. has more than 300 ports and receives some 6 million containers at those ports each year. However, prior to September 11, only 2 percent of those containers were physically inspected. In an age of nuclear proliferation and international terrorism, the vulnerabilities of maritime transport can no longer be tolerated.