Despite the increasing significance of customary law in the delimitation of sea boundaries between states, the principles that evolved during the three centuries prior to World War II have generally been ignored. Although a comprehensive study in this field is needed, the studies that exist begin either with the Truman Proclamation of 1945 or the discussions of the International Law Commission in the early 1950’s. The Commission itself declared that there was no law on the matter and attempted to legislate rules in the interest of the progressive development of international law. This hasty and ambitious attempt left a gap between the conventional law and customary law, which later resulted in many disputes.

The United States and Canada agreed, by the Boundary Settlement Treaty of March 29, 1979, to submit their decade-long dispute over the maritime boundary in the Gulf of Maine area to a Chamber of the International Court of Justice (ICJ) or to an ad hoc court of arbitration. The treaty, however, has not yet taken effect because the interrelated Fisheries Agreement, which was concluded on the same day and was to take effect simultaneously, was Unilaterally scrapped by the United States Government on March 6, 1981, on grounds of its allegedly unfair and inflexible provisions. On April 29, the United States Senate unanimously adopted a resolution supporting the Government's position to delink the two treaties and to settle the maritime boundary problem first by a third-party procedure. Whether or not a new fisheries agreement is concluded in the near future, it is expected that the maritime boundary dispute will ultimately be resolved by binding third-party settlement. The purpose of this article is to examine the legal position taken by each Government regarding the maritime boundary issues, and to suggest equitable principles that should govern their resolution.