Hot Line Agreement (1963)


Bilateral agreement establishing a direct communications link between U.S. and Soviet heads of state for use in "time of emergency." Seeks to reduce the risk of a nuclear exchange stemming from accident, miscalculation, or surprise attack. Both sides connected by transatlantic cable and radio telegraph circuits for continuous direct communications. Updated in 1971 to include two U.S.-U.S.S.R. satellite communications circuits, along with multiple terminals in each country. The treaty entered into force on June 20, 1963.


The need for ensuring quick and reliable communication directly between the heads of government of nuclear-weapons states first emerged in the context of efforts to reduce the danger that accident, miscalculation, or surprise attack might trigger a nuclear war. These risks, arising out of conditions which are novel in history and peculiar to the nuclear-armed missile age, can of course threaten all countries, directly or indirectly.

The Soviet Union had been the first nation to propose, in 1954, specific safeguards against surprise attack; it also expressed concern about the danger of accidental war. At Western initiative, a Conference of Experts on Surprise Attack was held in Geneva in 1958, but recessed without achieving conclusive results, although it stimulated technical research on the issues involved.

In its "Program for General and Complete Disarmament in a Peaceful World," presented to the General Assembly by President Kennedy on September 25, 1961, the United States proposed a group of measures to reduce the risks of war. These included advance notification of military movements and maneuvers, observation posts at major transportation centers and air bases, and additional inspection arrangements. An international commission would be established to study possible further measures to reduce risks, including "failure of communication."

The United States draft Treaty outline submitted to the ENDC 1on April 18, 1962, added a proposal for the exchange of military missions to improve communications and understanding. It also proposed "establishment of rapid and reliable communications" among the heads of government and with the Secretary General of the United Nations.

The Soviet draft Treaty on general and complete disarmament (March 15, 1962) offered no provisions covering the risk of war by surprise attack, miscalculation, or accident. On July 16, however, the Soviet Union introduced amendments to its draft that called for (1) a ban on joint maneuvers involving the forces of two or more states and advance notification of substantial military movements, (2) exchange of military missions, and (3) improved communications between heads of government and with the U.N. Secretary General. These measures were not separable from the rest of the Soviet program.

The Cuban missile crisis of October 1962 compellingly underscored the importance of prompt, direct communication between heads of state. On December 12 of that year, a U.S. working paper submitted to the ENDC urged consideration of a number of measures to reduce the risk of war. These measures, the United States argued, offered opportunities for early agreement and could be undertaken either as a group or separately. Included was establishment of communications links between major capitals to ensure rapid and reliable communications in times of crisis. The working paper suggested that it did not appear either necessary or desirable to specify in advance all the situations in which a special communications link might be used:

. . . In the view of the United States, such a link should, as a general matter, be reserved for emergency use; that is to say, for example, that it might be reserved for communications concerning a military crisis which might appear directly to threaten the security of either of the states involved and where such developments were taking place at a rate which appeared to preclude the use of normal consultative procedures. Effectiveness of the link would not be degraded through use for other matters.

On June 20, 1963, at Geneva the U.S. and Soviet representatives to the ENDC completed negotiations and signed the "Memorandum of Understanding Between the United States of America and the Union of Soviet Socialist Republics Regarding the Establishment of a Direct Communications Link." The memorandum provided that each government should be responsible for arrangements for the link on its own territory, including continuous functioning of the link and prompt delivery of communications to its head of government. An annex set forth the routing and components of the link and provided for allocation of costs, exchange of equipment, and other technical matters. The direct communications link would comprise:

  1. two terminal points with teletype equipment;
  2. a full-time duplex wire telegraph circuit
    (Washington-London-Copenhagen-Stockholm-Helsinki-Moscow); and
  3. a full-time duplex radiotelegraph circuit (Washington-Tangier-Moscow).

If the wire circuit should be interrupted, messages would be transmitted by the radio circuit. If experience showed the need for an additional wire circuit, it might be established by mutual agreement.

The "Hot Line" agreement, the first bilateral agreement between the United States and the Soviet Union that gave concrete recognition to the perils implicit in modern nuclear-weapons systems, was a limited but practical step to bring those perils under rational control.

The communications link has proved its worth since its installation. During the Arab-Israeli war in 1967, for example, the United States used it to prevent possible misunderstanding of U.S. fleet movements in the Mediterranean. It was used again during the 1973 Arab-Israeli war. The significance of the hot line is further attested by the 1971, 1984 and 1988 agreements to modernize it.

Source: Department of State