Since President Truman claimed zones of extended coastal jurisdiction for the United States in September 1945, the delimitation of zones of national jurisdiction between states with opposite or adjacent coasts has become a major legal and political issue in international relations. The development of the concept of the continental shelf during the 1950s and 1960s, as well as the claim to extended fisheries zones or exclusive economic zones by nearly all coastal states under the sway of the Third United Nations Conference on the Law of the Sea since the mid-1970s, gave rise to delimitation problems all over the world. Similar problems may arise if more states extend their territorial seas to 12 nautical miles, which they may do under the new United Nations Convention on the Law of the Sea (LOS Convention) of 1982. By now, a considerable number of delimitation agreements have been concluded on the continental shelf and/or the territorial sea, and even agreements on the delimitation of fisheries zones have been reported.

Liquid mineral deposits that extend across a national frontier on land territory or a dividing line on the continental shelf between adjacent or opposite states have increasingly attracted attention in international law during the last two decades. Several common deposits of petroleum or natural gas have recently been discovered, and since the early sixties a considerable number of international agreements have been concluded to deal with the problems of those deposits. This development gives rise to certain considerations regarding an emerging legal concept of cooperation between neighboring states, as has already occurred with water resources shared by two or more states.