292. Instruction From the Department of State to All Diplomatic Missions 1



  • International Conference of Plenipotentiaries on the Law of the Sea


  • CA–4339 of November 8, 1957

The present instruction is concerned with the use to be made by the field posts of the memorandum on “Factors Which Support the Maintenance of the Narrow Breadth of the Territorial Sea”, enclosed as Enclosure C to the reference instruction.2

The Embassy has discretion as to whether representations based on the memorandum are made and the extent of such representations. However, the Department hopes the Embassy will make the representations in the absence of over-riding circumstances.

The paragraphs which follow are for the Embassy’s general guidance in its consideration of the problem.

Section I of the memorandum deals with the effects upon maritime trade and commerce of an extension of the territorial sea. These are the considerations of a general character which are mentioned in the reference instruction as among those demonstrating why it is in the interest of the individual states to support the three-mile rule. Sections II, III and IV3 deal with the effects of such an extension upon international stability and the security of the nations of the free world. The considerations set forth in these three sections are basic to the position of the United States on the question of the [Page 600] breadth of the territorial sea and to its decision vigorously to support the three-mile rule at the forthcoming Conference on the Law of the Sea.

Notwithstanding the importance of the security considerations in the position of the United States on the territorial sea issue, the Department recognizes that political and other factors in some countries may make it undesirable to introduce them into the discussions. In other countries it may be desirable to cast the arguments of the memorandum in a different form.

In general the security considerations are particularly appropriate for pre-Conference discussions in countries that are tied to the United States by military agreement but whose position on the breadth of the territorial sea differs or may differ at the Conference from that of the United States. It is evident, however, that even in the case of countries that consider that their security interests fully parallel those of the United States, considerable variation is to be expected in the reaction to the points covered by the memorandum. The Embassy may consider that one or more of the points should be omitted. Attention is directed in particular in this latter connection to the first two paragraphs of Section III which relate to “Intelligence Collection”.

It is not intended by the preceding paragraph to exclude all the so-called “neutral” countries. The Missions in certain of these countries may find appropriate uses for the memorandum, particularly Section II relating to the preservation of neutrality.

In all cases where the memorandum is used, care should be taken to avoid giving the impression that the position of the United States on the maintenance of the three-mile rule rests solely on the considerations set forth in the memorandum. As indicated in the reference instructions, the position of the United States in maintaining that valid reasons have not been advanced justifying a change in the existing rule of international law on the breadth of the territorial sea has two principal aspects: that there are weighty reasons in the general interest (maritime trade and commerce and free world security) for retaining the three-mile rule and, second, that the national interests which have led to claims for a greater distance can be met by more effective methods (international cooperation for conservation along the lines of the ILC fisheries articles) than an extension of the territorial sea.

It is not the present intention of the Departments of State and Defense to send visiting teams for special briefings to the field as was done in the latter part of 1956 (see CA–316, October 26, 1956). Consideration, nevertheless, will be given to the views of the Embassy should it deem it desirable to have supplemental briefings by means of a field visit.

[Page 601]

As a measure which could usefully supplement the presentation of the case made in the reference memorandum, the Department of Defense has developed colored slides and explanatory material which graphically illustrate the security consequences, in terms of restrictions upon navigation and on naval operations, of an extension of the territorial sea. It is believed that the slides would be helpful in visually demonstrating the validity of the principal considerations of the memorandum. The possibility of having the slides duplicated in a manner suitable for showing to foreign officials by Embassy personnel is being explored. It is the Department’s hope that copies will be available for pouching in the near future to the Embassies that are likely to rely extensively on the “Factors” memorandum in the briefings. It is not suggested, however, that discussions on the basis of the memorandum be postponed until the slides are received.

The Embassy is requested to report as soon as possible significant reaction to any representations made on the basis of the memorandum.

  1. Source: Department of State, Central Files, 399.731/11–1557. Official Use Only. Cleared by several officers of the Department and by the Department of Defense. The message was repeated to Belgrade, Bucharest, Budapest, Cairo, Damascus, Kabul, Katmandu, Moscow, Prague, and Warsaw.
  2. Not printed.
  3. These sections dealt, respectively, with the effects on neutrality, military and naval operations, and air operations.