Over the course of the negotiations, several specific issues were solved with the aid of letters between cabinet level officials, primarily the U.S. Secretary of State and the Soviet Foreign Minister. None of these letters are legally binding agreements; rather they serve to clarify and resolve issues related to the Treaty, but outside its framework. The letters undertake no new commitments, except for the U.S. political commitment to terminate ballistic missile submarine operations at Holy Loch, Scotland, and the related Soviet political commitment not to establish similar facilities.


Although dated July 31, 1991, the contents of the exchange of letters on third-country basing was negotiated in late 1990. At that time, two issues concerning third-country basing were at issue: U.S. ballistic missile submarine operations from Holy Loch, Scotland, and Soviet insistence on some form of right to inspect U.S. forces abroad.

For almost 30 years the United States operated ballistic missile submarines from Holy Loch, Scotland. These submarines, although operating from Holy Loch for extended periods, were permanently based in the United States. As a result, the United States does not consider operations from Holy Loch to be "basing" within the meaning of that term in the Treaty. The Soviet Union, in contrast, regarded these operations as basing. The resulting impasse was broken following a U.S. decision -- made for programmatic, not arms control reasons -- to terminate operations at Holy Loch. Secretary Baker's letter informed the Soviets of that fact. Further, since the United States is shifting to a force of Ohio-class ballistic missile submarines, which operate from permanent bases without being supported by forward-deployed submarine tenders, Secretary Baker's letter further indicated that the United States would not establish facilities similar to Holy Loch in the future.

Secretary Baker's letter also noted the agreement, codified in paragraph (c) of the Eighth Agreed Statement, that the Parties "do not rule out the possibility" that inspections or visits might be used in the resolution of compliance debates involving third countries.

The Soviet response essentially repeated the points made by Secretary Baker, adding assurances that the Soviet Union had no arrangements similar to Holy Loch and would not establish such arrangements in the future.


The exchange of letters dated December 6, 1990, between Secretary Baker and Soviet Foreign Minister Shevardnadze served as the mechanism for the Soviet Union to drop its proposed ban on long-range non-nuclear ALCMs armed with two or more weapons. The sides had previously agreed to a ban on long-range nuclear ALCMs armed with two or more nuclear weapons (now codified in paragraph 18(e) of Article V of the Treaty). Soviet negotiators asserted that a companion ban on non-nuclear ALCMs with multiple weapons was necessary because a Party might otherwise use the testing of such a weapon to covertly develop a long-range nuclear ALCM armed with multiple nuclear weapons.

The letters, although dated December 6, were negotiated substantially earlier; their formal exchange was delayed until a convenient Ministerial meeting. In the U.S. letter, Secretary Baker made four substantive points. First, he reaffirmed the ban on long-range nuclear ALCMs with multiple nuclear weapons. Second, he expressed the U.S. interpretation that producing, testing, or deploying long-range non-nuclear ALCMs with multiple weapons "for the purpose of acquiring the capability in the future to deploy long-range nuclear ALCMs with multiple weapons" would be inconsistent with Treaty obligations. Third, Secretary Baker indicated that long-range non-nuclear ALCMs with multiple weapons, like any other long-range non-nuclear ALCMs, would have to be distinguishable from long-range nuclear ALCMs in accordance with provisions of the Treaty. Finally, the Secretary of State noted that a Party would have the right to raise any concerns or ambiguities within the framework of the Joint Compliance and Inspection Commission as specified for in Article XII of the then-current Joint Draft Text of the Treaty (Article XVI in the final Treaty).

None of these points constitute new obligations; they merely restate existing Treaty obligations. Thus this letter and the Soviet reply add no obligations to either Party. The Soviet reply repeated the same four points. Once again, this added no new obligations.


Tacit Rainbow was a proposed non-nuclear tactical cruise missile under development with a range (as range is defined in the START Treaty) of between 600 and 800 kilometers. Tacit Rainbow was planned for deployment on both tactical aircraft and heavy bombers. The Tacit Rainbow system has subsequently been cancelled, but in May 1990 the United States still expected to deploy the system and sought to ensure that Tacit Rainbow would not be treated as a long-range nuclear ALCM under START.

During the May 1990 Moscow Ministerial, the United States and the Soviet Union reached agreement on a number of issues related to long-range ALCMs, including accepting a 600 kilometer cut-off range for defining "long-range" nuclear ALCMs. As part of this overall solution, the Parties reaffirmed the agreement reached in June 1988 that "existing" long-range ALCMs would all be considered to be nuclear under START, while "future" long-range ALCMs would be considered to be nuclear unless they were distinguishable. At issue was the cut-off date for dividing existing systems from future systems.

The United States proposed, and the Soviet Union accepted, initial flight testing from a heavy bomber on or before December 31, 1988 as the appropriate cut off (this provision is now codified in paragraph 9(f) of Article III of the Treaty). Since Tacit Rainbow had not been flight-tested from a heavy bomber on or before that date (although it had been flight-tested from another airplane before that date), Tacit Rainbow could then, under this criterion, be treated as a long-range non-nuclear ALCM distinguishable from long-range nuclear ALCMs, and not be captured under START.

While accepting the basic approach, the Soviet Union expressed concern about the Tacit Rainbow system, that long-range non-nuclear cruise missiles could be used to provide heavy bombers with a long-range nuclear ALCM capability. As a result, the U.S. Secretary of State, on May 19, 1990, sent the Soviet Foreign Minister a letter seeking to clarify the situation with regard to Tacit Rainbow. The contents of this letter were not negotiated or discussed with the Soviet Union in advance.

In the letter the United States made three substantive points. First, Secretary Baker reaffirmed the acceptability of the December 31, 1988, cut-off date to distinguish between current and future long-range ALCMs, noting that, under such a cut-off date, Tacit Rainbow would be treated as a future non-nuclear ALCM. Second, the Secretary of State provided formal assurances that Tacit Rainbow was a non-nuclear ALCM and thus would be covered by the Treaty provisions governing long-range non-nuclear ALCMs. Finally, the Secretary of State indicated that the range of Tacit Rainbow was between 600 and 800 kilometers. This final point had no bearing on the treatment of Tacit Rainbow, since all ALCMs with ranges greater than 600 kilometers are considered "long-range" ALCMs under the Treaty.

The letter involves no undertakings on the part of the United States. It does, however, provide a formal U.S. assurance that Tacit Rainbow was not a long-range nuclear ALCM and that the United States had no plans to provide it a nuclear capability. Based on these assurances, the Soviet Union accepted the U.S. approach to distinguishability between long-range nuclear and long-range non-nuclear ALCMs and accepted the December 31, 1988 cut-off date.


During a September 1990 Ministerial Meeting between Secretary Baker and Soviet Foreign Minister Shevardnadze, held in New York City on the margins of the United Nations General Assembly, the sides, among other things, agreed on the provisions on heavy ICBMs now in the Treaty. Part of that agreement is reflected in the provisions of paragraph 2(d) of Article V and in the Fifth Agreed Statement. Taken together, these provide a limited right to relocate heavy ICBM launchers in exceptional circumstances. Although the "exceptional circumstances" were not spelled out, both Parties understood them to be circumstances arising from the turbulent internal political situation in the Soviet Union, which suggested the possibility that the Soviet government might desire to make such relocations as a consequence of the increasing local and republic autonomy within the Soviet Union.

During a subsequent visit to the Soviet Union, the Secretary of Defense pressed the Soviet Defense Minister about their need to construct new SS-18 silos. The Soviet Defense Minister responded that there were no such plans, thus casting doubt on the Soviet need for the provisions the United States had accepted in New York. As a result, the United States sought clarification.

An initial (undated) letter from Soviet Defense Minister Yazov to Secretary of Defense Cheney, provided partial clarification, but did not address all U.S. concerns. While it reaffirmed the Soviet obligation that any new silos would be constructed "simultaneously with the elimination" of older silos and thus that the limit of 154 heavy ICBM launchers would not be exceeded, it gave no insight to the circumstances which might require new construction.

The December 6, 1990, letter from the Soviet Defense and Foreign Ministers to the United States Secretaries of State and Defense provided that clarification. It reaffirmed earlier Soviet assurances that the limits of the Treaty would not be exceeded. This second Soviet letter cited two reasons for replacing heavy ICBM silos, both reflected in the Fifth Agreed Statement. The first was the possibility of accident. The second was the possibility of relocation "for non-military considerations, particularly in connection with the internal political developments that are taking place in our country." The Soviet letter noted that the Soviet Union had no current plans for such relocation.

The Soviet Foreign Minister communicated with the U.S. Secretary of State again on December 30, 1990, in a letter addressing a series of issues that had arisen out of the Houston Ministerial of December 1990. In that letter, Foreign Minister Shevardnadze reconfirmed the conditions of new heavy ICBM silo construction. Specifically, he reconfirmed that construction of new heavy ICBM silos could be undertaken only to replace heavy ICBM silo launchers destroyed in an accident or to relocate such launchers threatened by internal political emergencies. Consequently, the Soviet Foreign Minister concluded that the replacement of heavy ICBM silo launchers did not include the possibility of extensive new silo construction.

Based on these clarifications, the United States confirmed the agreement reached in New York and accepted the heavy ICBM provisions negotiated there. The Soviet letters provide formal confirmation of the intent of the Parties that relocations of heavy ICBM silos not result in exceeding the limits of the Treaty and that such relocation only be allowed in the case of extraordinary circumstances of a non-military nature relating to internal Soviet political factors.