America first claimed jurisdiction over its continental shelf in 1945, a few weeks after Japan’s surrender in World War II. For several years, the U.S. government had been concerned about Japanese ships catching salmon off Alaska, as well as other nations drilling for oil off American shores. With the war over, President Harry Truman proclaimed that an underwater area of some 750,000 square miles—about 4.5 Californias—now belonged to America.
No internationally agreed-upon definition of continental shelves existed until 1958, when 86 countries gathered at the first UN Convention on the Law of the Sea. The group decided, somewhat unhelpfully, that a shelf could extend as far and as deep as a nation could drill. By the following decade, technology had advanced so quickly that a country could claim virtually an entire ocean. Sure enough, one member of Congress from Florida proposed that the U.S. occupy what amounted to two-thirds of the North Atlantic.
President Lyndon B. Johnson warned against such expansionism. In a 1966 speech, he denounced the “new form of colonial competition” that threatened to emerge among maritime nations. “We must ensure that the deep seas and the ocean bottoms are, and remain, the legacy of all human beings,” he said. The following year, Arvid Pardo, an ambassador from Malta, called on the UN to deem the ocean floor “the common heritage of mankind.” In 1970, the U.S. voted alongside 107 other nations to do precisely that.
The UN reconvened in 1973 to legislate a shared vision of the seas. Over the next nine years, more than 150 nations and as many as 5,000 people gathered for off-and-on negotiating sessions in New York City and Geneva. They discussed a wide range of topics—freedom of navigation, fishing, scientific research, pollution, the seabed—and ultimately produced the Law of the Sea.
The U.S. had helped pave the way. Three years before the convention, the Nixon administration had presented a draft treaty that proposed a forerunner to the International Seabed Authority: an agency established by the Law of the Sea that would collect royalties from underwater resources and distribute them to the developing world. But the nation’s posture changed after Ronald Reagan’s election in 1980. American delegates began showing up to negotiating sessions wearing ties that bore the image of Adam Smith, the father of free markets. It was an early sign of the administration’s reluctance to regulate the maritime economy.