282. Memorandum Prepared in the Department of the Navy1


An extension of the territorial sea beyond a narrow belt may, on cursory examination, offer an apparent economic advantage to the coastal state in assuring to it the exclusive right to exploitation of the fisheries resources within those areas. Any discussion of the consequences flowing from a universally agreed upon breadth of the territorial sea must, however, take into account not only those immediate consequences to the coastal state but also the more far reaching effects upon maritime trade and commerce and upon international stability and the security of the nations of the free world.

I. Effects upon Commerce and Navigation of a Twelve-Mile Rule

Difficulties of Navigation Beyond Twelve Miles

The difficulties and uncertainties of piloting are substantially augmented by navigation beyond twelve miles. The reasons for this are various. Many landmarks employed in visual piloting are not visible at a range of twelve miles. Only 20 per cent of the world’s lighthouses have a range of twelve miles or more. Radar navigation at twelve miles and beyond is of only marginal utility in most instances because many targets normally used for radar navigation are unidentifiable at such distance. Thus, the more closely ships can pass to a coastline, the more accurate and safe their navigation. The seizure of the Swedish ship “Flying Clipper” by the Russians in the Baltic Sea on 29 August is a case in point. That ship had crossed into the Soviet twelve-mile zone because it had drifted off course in a storm during the night and wanted to use the Baltic lighthouses to check its position.

Consequences of Subjecting Shipping to Sovereignty of Coastal State within Twelve Miles

For the reasons outlined, ships find it convenient to navigate within twelve miles of a coast but beyond three miles (except when proceeding into port) and are therefore beyond the sovereignty of a coastal State with a three-mile territorial sea for all purposes other than that limited form of jurisdiction exercised in the contiguous [Page 560] zone, i.e., prevention of infringement of customs, fiscal and sanitary regulations. In the event of a collision involving ships navigating in such waters, namely three-twelve miles or in the event of any other incident of navigation in such waters involving the penal or disciplinary responsibility of the master or of any other person in the service of the ship, proceedings may be instituted against such persons only before the authorities of the flag flown by the ship or of the State of which such persons are nationals. While on the high seas no arrest or detention of the vessel may be ordered, even as a measure of investigation, by any authorities other than those whose flag the ship is flying. Any extension of the breadth of the territorial sea will subject ships passing through the extended area, the masters of those ships, and the members of their crews to arrest and detention by the coastal state. The potential interference with normal commerce which would accompany the adoption of a broad territorial sea can thus be readily foreseen. The Suez Canal crisis amply demonstrates the danger to world peace and stability created by unilateral action, albeit legal, taken by a coastal State which affects merchant shipping to the point of exerting the power of life or death over world commerce. The increased risk of interference with the normal passage of ships proceeding through a twelve-mile territorial sea would result in increased insurance rates and, consequently, increased shipping costs. Efforts by merchant ships to avoid such interference by navigating beyond the territorial sea would result in longer, less economical runs and hence in the incurrence of increased shipping rates. The brunt of such increase in rates is borne ultimately, not by the nations engaging in maritime commerce, but by those nations dependent upon that commerce for their economic existence.

The very factors which render navigation difficult and uncertain at a distance of twelve miles from shore will themselves give rise to myriad disputes where the issues of jurisdiction will be one involving disproportionate expense and time consumption by virtue of the extreme difficulty of proving a vessel to have been within or beyond a twelve-mile limit. The danger that such disputes may give rise to international incidents with an accompanying increase in international tensions is one which has already materialized. The seizure of the Swedish ship in the Baltic by Russian forces is a case in point, as are the seizures of United States and Cuban shrimp boats off the coast of Mexico, and those of Japanese fishing boats by South Korea. To adopt a twelve-mile rule which for the reasons stated would inevitably lead to an increase in the number of such incidents, would be to knowingly place in jeopardy world peace and stability.

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Burden Imposed upon Coastal State of Patrolling a Broad Territorial Sea

Any extension of the breadth of the territorial sea would impose a burden on the coastal State to patrol effectively the larger area. This burden would entail a concomitant increase in the fiscal expenditures of the coastal State stemming from an increased workload in both merchant marine safety and law enforcement. For example, the United States estimates an approximate initial outlay of $8,000,000 and an increase in annual operating cost of $1,500,000 per hundred miles of coast for an extension of the territorial sea from three to twelve miles. Any failure by a nation to exercise effective control over areas to which it has laid claim would risk the incurrence of international embarrassment to the nation asserting the claim. At least one nation is presently faced with this realization. Sporadic attempts at enforcement would only result in an increase of international disputes and international tensions.

II. Preservation of Neutrality

The neutralist tendencies and policies of some states are sufficiently clear to suggest that in a future conflict neutrality and the international law pertinent thereto will be matters which may have to be taken into account. It is with this thought in mind that one can approach the question of what effects are likely to be generated should the territorial waters of a neutral be extended from three to twelve miles in breadth. There are certain facile attractions to the twelve-mile limit for a neutral State. If it could safely be assumed that the contending belligerents would respect the territorial sea of a neutral, the possibility of hostile incursions into neutral coastal areas would be materially lessened. Such an assumption would not, unfortunately, be justified. There are many historical illustrations which demonstrate that belligerents have been less than circumspect in their observance of the sanctity of neutral waters. In this regard there is little prospect that the acts of belligerents in a future war will vary in pattern from the past. Moreover, it may be safely assumed that a belligerent in any future war would be even less inclined to accord complete respect to a twelve-mile coastal belt of neutral waters than to a three-mile zone—particularly in view of the probable inability of the neutral to control the broader belt. The problem of the neutral with a twelve-mile territorial sea in defending itself is further demonstrated by the greatly increased ocean areas which would have to be patrolled to insure the inviolability of its sovereignty. As an example of this, the position of traditional neutrals, e.g., the Scandinavian countries, who claim only a three-mile territorial sea for purposes of defense, while claiming a broader belt for other purposes, is significant.

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To illustrate the attractiveness of neutral waters to a belligerent, we turn to the submarine. For reasons of its own safety, a submarine will seldom attempt to operate within three miles of shore. The hazards to a submerged submarine are usually lessened materially as the distance from shore increases. Thus, it can be seen that a belligerent submarine might look upon a neutral with a broad territorial sea as offering a particularly attractive haven if she were hard pressed by anti-submarine aircraft or surface vessels of the enemy.

Similarly, other combatant types of belligerent merchantmen may be enticed within the territorial waters of a neutral hoping, however wishfully, to find there a safe refuge from pursuit by enemy forces. There is still another factor which would serve to lure belligerent vessels within twelve miles of a neutral coast. For reasons already discussed, navigation at a distance of twelve miles from shore is, in most cases, inexact and unsatisfactory for purposes of accurately ascertaining a ship’s position. Captains and masters are accordingly strongly disposed to navigate at a distance less than twelve miles from charted navigational objects on shore. In view of all of these considerations, belligerent violation in time of international conflict of the sovereignty of a state with a twelve mile territorial sea, unwittingly or otherwise, is highly probable. It would be unduly optimistic to expect one belligerent to stand idly by while the ship of another belligerent entered the territorial sea of a neutral either by accident or design. In such a case the neutral may not reasonably expect the belligerent to seek his remedies through diplomatic protest. Rather, it is believed that a solution of the problem would more likely be sought through the belligerent’s resort to self-help. Having the war brought to the neutral’s doorstep in this manner would appear altogether likely in the event the neutral were unable to exercise adequate means to preserve its neutrality. Under such circumstances, the ability of a neutral to remain neutral would be highly problematical.

It is highly likely that the ships of a neutral would be drawn into hostilities in attempting to repel belligerent incursions into its territorial sea. At the very least, strained diplomatic relations with the belligerent nation which felt itself aggrieved by the neutral nation’s failure to prevent belligerent use of its territory would result. Repeated belligerent use of the territorial sea of a neutral by one belligerent could, not unlikely, lead ultimately to the invasion of the neutral by the opposing belligerent.

The possibility of belligerent use of the territorial sea of a neutral as a base of operations, as a refuge, or as a means of transit [Page 563] (such as in the case of the Altmark in World War II)2 cannot be increased with any increase in the limit of the territorial seas. A three-mile zone would appear to reduce the possibility of belligerent violation, and to that extent would tend to insure a neutral state’s remaining neutral in the event of a future war.

III. Effects upon Military and Naval Strategy and Tactics

Intelligence Collection

The possession of adequate photographic and visual intelligence is vital to many military operations. Amphibious operations, bombing missions, mine-laying and mine-sweeping operations, missile guidance—all are dependent upon information assembled from intelligence. In the collection of such intelligence ships and aircraft fulfill a vital role. The intelligence obtainable from photographs taken at three miles, particularly when taken from a ship, is of considerable value, but that from twelve miles is negligible. If an aircraft engaged in low altitude photo reconnaissance could operate approximately three miles from a coast, the depth of photo penetration would be nine miles further inland than if the aircraft were operating just outside a twelve-mile limit.

Photographic reconnaissance is particularly vital to amphibious planning and operations as well as special attack missions. Close-in beach photographs, for example, which have sufficient detail, will provide information on obstructions, gradients, tidal range, consistency and composition of the soil, defenses and defensibility, traffic-ability, accesses, landing points, underwater depths, reef and bar areas. Further, for minimum altitude special weapon attack approaches, the photo aircraft must be able to approach as close as possible to the beach or target area in order that the landfall check points, en route landmarks, initial point, and if possible, the target itself, will all be visible on the photographs. With present equipment, satisfactory low-level attack photography can be obtained at a six-mile range under ideal conditions; however, it is considered most desirable to obtain coverage in to three miles. (Annex I)3

Restrictions upon Operational Mobility

Modern concepts of war consider the use of nuclear weapons, and therefore task groups are dispersed for defense against attack. In order to maintain the highest state of readiness practicable frequent [Page 564] exercises are held in which two or more task groups participate. Defense against nuclear attack and realistic training require freedom to maneuver and the use of as many high seas passages as can be made available. When, in the Mediterranean Sea, for example, high seas passages are reduced in number, thereby curtailing the flexibility and maneuverability of task groups, effective exercises are difficult to conduct.

The following criteria have been used to establish the reduction in maneuverability of a task group operating in a sea where the territorial waters of adjacent countries are extended from three to twelve miles.

Unlimited maneuverability requires sea room to conduct offensive and defensive aerial and submarine warfare maneuvers.

Limited maneuverability requires sea room to zigzag and the ability to avoid interference from other surface traffic.

Marginal maneuverability requires sea room to maintain a formation of minimal diameter.

Increasing territorial waters from three to twelve miles in the Mediterranean Sea would have a pronounced effect upon high seas maneuverability in those waters. In a passage where adjacent states have a limit of three miles, a single ship or column of ships could effect high seas transit if the passage were more than six miles in breadth. There are 38 such passages in the Mediterranean Sea. The effect of increasing the breadth of the territorial sea to twelve miles in that area would be extensive. For example, of the 38 high seas passages now available to single ship movement, only 16 would remain with a twelve-mile territorial sea in force. In like manner, of the twelve high seas passages in the Mediterranean now available for unlimited task force maneuverability, only three would remain.

Maneuverability on the high seas would be similarly severely restricted in the Baltic Sea, the South China Sea, the Sea of Japan and the Java Sea—to mention but a few potentially critical areas.

For the sake of illustration, we shall examine the effect in distance and time if a task group were ordered to proceed from Guam to Saigon in the event a twelve-mile rule were adopted. At the present time the shortest high seas route is through the Suragao Straits—a route of about 2200 miles. If a twelve-mile limit were in force and the task force were required to take a route to the north of Luzon to remain outside the twelve-mile limit, the route would be increased in length to 2600 miles, or by using a 16 knot speed of advance, the steaming time would be increased by 25 hours. If for strategic or tactical reasons the route north of Luzon proved undesirable, the only alternative would be one via the Makassar Strait, the Java Sea and the South China Sea—a route of about 3500 miles. Here the steaming time at 16 knots would be increased by 81 hours. [Page 565] Pursuing this latter route, through rather restricted waters, would permit only marginal opportunities for flight operations, zigzagging or stationing of pickets.

Thus, it can be seen that any extension of the territorial sea constitutes an encroachment upon waters which now constitute the high seas and could operate to restrict severely the mobility of the fleet and fleet operations.

Restrictions upon Mobility of Soviet Submarines

In order to prevent, in any future war, a repetition of the extensive damage to allied shipping and general disruption of sea lines of communications wrought by the German U-Boat fleet in World War II, sound strategy would call for denying enemy submarines free access to the high seas.

The Russian Navy now has a large, modern submarine fleet. There is no reason to deny Soviet capability of building submarines capable of launching guided missiles against coastal cities and industrial complexes.

One of the most effective ways to combat this submarine menace would be the employment of various types of blockade in order to prevent as many as possible from reaching the open sea.

In the North Atlantic, for example, Russia has only two avenues of access to the open seas; namely, through the Barents Sea and through the Baltic. Sound strategy would, for example, dictate that a barrier patrol be set up between Iceland and Norway to prevent passage of Russian submarines. It is apparent that if … were neutral and had a twelve-mile territorial sea, which allied ships could not penetrate, a possible avenue of escape twelve miles wide would be provided for the Russian submarine. Russian strategy is apparently heavily dependent on a large submarine fleet operating on the high seas. There is no doubt that they would use any means to get their boats to sea, and violation of a neutral’s territorial waters would most likely cause them very little concern.

Allied policy in general would most likely be against violation of neutral waters except under circumstances of known violation of those waters by enemy forces. The crucial point is that with a twelve-mile band of territorial sea along the coast of any country, enemy submarines could pass through those waters undetected. With a three-mile limit in effect, this sort of passage would be less likely. This situation would likewise exist in the Mediterranean and in the Far East—Russia’s only other accesses to the high seas.

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In summation, an extension of the territorial sea to twelve miles would remove an area of more than 3,000,000 square miles from the domain of the high seas. Such an extension although perhaps gaining an apparent economic advantage for the nation claiming it, would work against a nation’s fiscal interests in terms of the increased burden of effectively patrolling the enlarged area. A broad limit would jeopardize the status of a neutral in any future conflict. Universal recognition of a broad territorial sea would encumber maritime commerce and navigation throughout the world and would result in an increase of disputes and international tensions. Most important from a military point of view, such an extension would hamper intelligence collection activities, restrict fleet mobility, and permit greater mobility to Soviet submarines. The cumulative effect of these considerations would be to disserve the cause of world peace and undermine the security of the free world.

  1. Source: Department of State, Central Files, 700.022/10–2456. Confidential. Copy obtained from the Department of the Navy on October 25, 1956, by Marjorie M. Whiteman, Assistant Legal Adviser for Inter-American Affairs.
  2. The Altmark, a German prison ship, had entered Norwegian territorial waters. England protested to Norway and upon the failure of the Norwegian government to force the Altmark from its territorial waters, HMS Cossack entered Norwegian waters and captured the Altmark, 25 March 1940. [Footnote in the source text.]
  3. Entitled “Photographic Interpretation”, not printed.