The Deputy Under Secretary of State (Matthews) to the Assistant to the Secretary of Defense for International Security Affairs (Burns)1

top secret

My Dear General Burns: The Turkish Government has under consideration a proposed plan for controlled mining of the Turkish Straits as part of a Bosphorus Sea defense project. It is probable that as a prerequisite to Turkish approval of the plan, the United States Government may have to indicate its strong support and, in addition, urge the British Government to indicate to the Turkish Government its concurrence in principle thereto.

It is understood that the mining project is strongly endorsed by the Joint American Military Mission for Aid to Turkey, particularly by the Naval Group, and that it is of considerable interest to the United States Department of the Navy. While the competent Turkish military authorities agree on the desirability, from the military point of view, of this project, the Turkish Foreign Office is concerned over the very important political considerations which are involved. These considerations relate principally to Turkey’s obligations under the Convention regarding the Regime of the Straits, signed at Montreux in 1936, to which the United States is not a party, and to the general question of Soviet reaction in the event the Straits are mined. The following background relates to these considerations:

In April 1950 the Turkish Government informally requested the views of the Department as to whether the proposed mining of the Straits would be in violation of the Montreux Convention.2 On the [Page 1114] basis of information given to it regarding the project, the Department concluded that it would not constitute an infraction of the Convention. According to this information, the project involved mines laid at a depth of 20 to 30 fathoms near the Black Sea entrance to the Straits and controlled from a harbor entrance post. They would allegedly constitute no deterrent or danger to navigation, since when not energized the field could be crossed at any point without pilotage and since moored mines which broke loose would be sterile.

The British Government, which was a signatory to the Convention and which is also bound to Turkey through the British-French-Turkish Treaty of Mutual Assistance of 1939, was likewise requested by the Turkish Government to indicate its views. On a strictly juridical basis, these views, expressed in an aide-mémoire dated June 19, 1950, corresponded to those of the Department, but the British discouraged implementation of the project on the ground that (1) it might involve the Turks in political and legal controversies since mere knowledge of the existence of the mines might be considered a deterrent to complete freedom of transit, and (2) mining of the Straits in advance of any imminent danger of war would appear impracticable because of constant maintenance requirements of underwater installations.

The Turkish Foreign Minister, on January 11, 1951, told our Ambassador that the Government’s primary political interest in the matter was that such action as it might take be irrefutably correct and consistent with its obligations under the Montreaux Convention. He added that the British aide-mémoire was definitely, perhaps intentionally, equivocal and that this aspect should be forthrightly cleared up by the British. He indicated, however, that he would submit the matter to the Cabinet at its next meeting. At the same time he stated that if the project were implemented, the Soviets might be expected to charge a violation of the Convention with a view to reopening the question of its revision, so that there was strong reason for Turkey to be sure that it was clearly in the right. The Embassy advanced its own view that if the project were pushed by the United States the Turkish Government might well exploit any resulting Soviet hostility to urge the need for a United States security commitment.3

The American Embassy at Moscow in a telegram of December 22, 1950, expressed the view that the mining would be capitalized on to intensify the current war of nerves against Turkey and doubted that technical justification under the Montreux Convention on the basis of the harmlessness of the mines would be sufficient to counteract the public effect of Soviet protests against their presence. It strongly [Page 1115] opposed implementation of the project unless it is considered a vital defense measure for which there is no feasible alternative.4

It is the Department’s understanding that while the mines would be relatively ineffective with respect to surface targets and would not, therefore, supplant other types of mines which would have to be laid in the event of hostilities, they would aid in the detection of submerged submarines which may endeavor to transit the Straits surreptitiously. However, since other detection systems are or will be installed in the Bosphorus area, the question arises whether the installation of the mines as an additional detection device or for the other purposes which they might serve will contribute sufficiently to United States security to justify the United States urging the Turkish Government to approve the project, despite the possible consequences.

Although the Turkish Government has not expressed an expectation of receiving a security commitment from the United States before proceeding with implementation of this project, pressure on our part might result in their asking for such a commitment. The minimum request which the Turkish Government is expected to make is that the United States Government actively support the Turkish Government in this project and also that the British give similar support (which the United States may have to take the initiative to obtain).

The Department would therefore appreciate receiving your views as to the importance of this project from the military standpoint, including an indication of the essentiality of the project to United States security.5

Sincerely yours,

H. Freeman Matthews
  1. Drafted by Snyder and Moore, GTI, and cleared with George H. Emery, S/ISA, and Richard H. Davis, EE.
  2. For previous documentation regarding the proposal to mine the Turkish Straits, see Foreign Relations, 1950, vol. v, pp. 1224 ff.
  3. Presumably the reference is to telegram 422, January 12, 1951, from Ankara, which is printed in Foreign Relations, 1950, vol. v, p. 1353.
  4. Presumably the reference is to telegram 1227, December 22, 1950, from Moscow, which is printed in Foreign Relations, 1950, vol. iv, p. 1281.
  5. General Burns acknowledged receipt of this letter on February 6 and informed Matthews that the Department of Defense was studying the question of controlled mining of the Turkish Straits (782.5/2–651).