DHS lays out four primary ways terrorists could exploit the maritime domain to cause death and destruction. The most serious and likely threat is the aforementioned WBIED attack, used in the U.S.S. Cole attack as well as against the French oil tanker M/V Limburg in 2002, also off the coast of Yemen. Second, small vessels could be used to smuggle weapons into the United States, possibly weapons of mass destruction. Third, small vessels could transport terrorists onto American shores, exploiting the country’s most porous and unsecured border. And fourth, small vessels could be used by terrorists to sneak ashore for a strategic attack. The latter occurred during the November 2008 terrorist attack in Mumbai, India. Ten jihadist terrorists from Pakistan came ashore on inflatable speedboats after launching from a fishing trawler they had pirated. More than 170 people were murdered in the attack as the terrorist commandos sowed chaos across the city for three days.
A successful attack in U.S. waters could have a devastating economic impact on the nation. In 2008, then-USCG Admiral Thad Allen noted in an article for the U.S. Naval Institute’s magazine Proceedings that the U.S. maritime transportation system adds $700 billion to the U.S. economy annually, calling it “the lifeblood of our economy.” To stress his point, he noted that when labor disputes shut down the ports of Long Beach and Los Angeles in 2003, the American economy suffered losses estimated at $1 billion per day. His point was clear: a successful maritime terrorist attack could do the same or worse.
And while the threat level may currently be considered moderate, maritime security stakeholders interviewed for this article all agreed that an eventual attack is likely—the only open question being when it might occur.