The US Coast Guard has four principal missions: (1) Maritime Safety; (2) Maritime Law Enforcement; (3) Marine Environmental Protection; and (4) National Defense. Although the first major review of Coast Guard roles and missions since 1982 was recently completed, these four basic US Coast Guard missions are unlikely to change.³³ The missions are supported by seven major operating program areas of the Coast Guard, as detailed in Figure 2, including particularly “Enforcing Maritime Laws and Treaties”.³⁴

　

　　The US Coast Guard's Maritime Law Enforcement (MLE) Program is responsible for enforcement of laws and treaties in three major areas--Living Marine Resources, Drug Interdiction, and Alien Migrant Interdiction.

The Coast Guard is responsible (with the National Marine Fisheries Service) for enforcing applicable fisheries laws for conservation and management. The Coast Guard responsibility is defined by the US Exclusive Economic Zone (EEZ). The US has the largest EEZ of any country in the world, over 2.25 million square miles and 90,000 miles of coastline. Fisheries in the US is a $25 billion per year industry. The Coast Guard also works closely with foreign countries to ensure compliance with international laws and treaties, such as the UN prohibition on large scale high seas drift net fishing. For example, in June 1997, a ship (falsely claiming PRC nationality) illegally fishing with drift nets in the mid-Pacific, was seized by the US Coast Guard in an operation that covered 1700 miles over twenty days.³⁵ The Coast Guard also enforces legislation on the safety of commercial fishing vessels, and the Marine Mammal Protection Act.

The Coast Guard is the lead federal agency for maritime drug interdiction, and shares lead responsibility for air interdiction with the US Customs Service. As the key player in combating the flow of illegal drugs to the US, the Coast Guard mission is to reduce the flow of drugs from the (primarily South American) source by interdicting smugglers in the 6 million square mile area Transit Zone, including the Caribbean, Gulf of Mexico, and Eastern Pacific, under the multi-year Campaign Steel Web, part of the US National Drug Control Strategy. Coast Guard drug interdiction accounts for nearly one-quarter of all US government seizures of cocaine and marijuana each year. In 1997, the Coast Guard seized $4 Billion in cocaine alone, as over 70 percent of cocaine traffic now goes by sea. The Coast Guard depends on cooperation with other Caribbean nations, and is the lead agency for such cooperation.

The third area in US Coast Guard Maritime Law Enforcement is Alien Migrant Interdiction, where the Coast Guard is also the lead federal agency in enforcing US laws and policies to reduce the number of undocumented migrants entering the US by sea. To accomplish this, the Coast Guard conducts patrols and coordinates with other federal agencies and foreign countries to detect and interdict illegal migrants at sea, before they actually enter the country and require lengthy and costly deportation processes. Current major maritime migrant threats are from Cuba, Haiti, the Dominican Republic, and the PRC. Since 1980, the US Coast Guard has interdicted over 290,000 migrants from 44 countries.³⁶

　

　　As a percentage of all the Coast Guard's missions performed in “deepwater” (greater than fifty miles from shore), the Coast Guard law enforcement missions constitute 65 percent of ships hours and 35 percent of aircraft hours, by far the greatest of the four major mission areas. Also of interest, these law enforcement missions, when involving boarding foreign flag vessels on the high seas, give rise to sensitive and complex policy and international law issues.³⁷