Why the Three-Mile Limit Sank

ON Dec. 28, the Reagan administration took a little noticed but momentous step. The limits of the territorial seas of the United States were expanded from three miles to 12. The end of the limits, especially famous during Prohibition, was facilitated by changes in naval strategy and, ironically, by provisions of a treaty the United States has refused to sign. The three-mile limit was first established by Congress in 1794 when war broke out between Great Britain and France. The United States, according to a study on ``The Sovereignty of the Sea,'' by T.W. Fulton, ``found it necessary to define the extent of the line of territorial protection which they claimed on their coast, in order to give effect to their neutral rights and duties.'' At the time the three-mile limit was introduced it represented the farthest range of artillery and thus the effective limits of control by the coastal state. The limit was reaffirmed under the necessities of the Civil War by Secretary of State Seward in 1862 and, again, during the period of Prohibition, in 1924, by Secretary of State Charles Evans Hughes.

Developments in the 20th century put new pressures on these previous policies. The independence of former colonies created nations that wished, for both economic and political reasons, to extend their control over adjacent seas. And naval strategy and technology changed; the potential range of artillery far exceeded three miles.

The United States, however, for many years resisted changes in the maritime boundaries, including the move by many nations toward a 12-mile limit. The paramount concern was that the extension of territorial seas would reduce the capacity of the US Navy to operate on a global basis; if every coastal state expanded the limits to 12 miles, the open seas available for free navigation would be substantially lessened.

A second concern relates to the right of free transit through straits, a matter of major importance to a global naval power. The extension of territorial seas out three miles from each shore meant, in most cases, that waters in the center of the straits remained international and thus unrestricted. The establishment of a 12-mile limit would extend territorial seas across more than 100 straits and, in the absence of some understanding on transit, place such transit under control of the coastal states.

In 1958, the first United Nations Conference on the Law of the Sea assembled in Geneva. Through the many sessions that followed before the majority of nations agreed on an international treaty, the limit of territorial seas and the rules governing transit through straits were central issues. More and more countries agreed to the 12-mile limit. Although the US put forward various alternative proposals, Washington was not prepared to follow the lead of other countries. The Department of Defense and, particularly, the Navy resisted any such change. Not only were the US authorities concerned over the extension of territorial seas, but they also stoutly resisted any formula that would increase the control over straits and raise the possibility that US warships, both surface and submarine, might need to request permission from a foreign government in order to transit such straits.

The pressure grew for change, however. The US fisheries industry wanted wider control over offshore activity by foreign fleets. Within the United Nations Conference, the adoption of the 12-mile limit came to be linked to other issues of concern to the US. Washington insisted on a provision granting innocent passage (passage without notification) for aircraft and warships through and over straits.

Ironically, upon completion of the treaty, the Reagan administration refused to sign, taking the position that the treaty largely codified customary international law, most of which the United States observed. As more and more nations adopted a 12-mile limit it became less and less possible to defend the three-mile limit on the basis of customary law.

The US Navy became more concerned that the adherence to the three-mile limit permitted Soviet intelligence vessels to approach close to US shores.

Thus did the combined pressures result in the White House statement of Dec. 28 changing a two-centuries-old approach to territorial waters. But no one can accuse the United States of precipitate action in making the change. The United States is the 105th nation in the world to move to a 12-mile limit.