165. Paper Prepared by the National Security Council Staff1


The following material discusses the features of the new SALT TWO concept, makes several observations on its overall relative merit, and offers some variations that may improve its chances of success.

Discussion of the Features of the New SALT TWO Concept

Reductions. The proposed aggregate level (2200) and MIRV level (1200) would be a significant improvement over the Vladivostok levels which clearly exceed our strategic requirements.

The reduction to 2200 will not impact on planned US programs; a few mothballed B–52’s will have to be eliminated initially with additional older systems (older B–52’s, Titan, and Polaris) eliminated in the early 1980’s if B–1 and Trident are deployed. On the other hand, the Soviets will be required to eliminate immediately about 300 delivery vehicles.

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The first impact of the MIRV limit would occur in mid-1983 when the initiation of sea trials for the 7th Trident submarine would put the US over the 1200 MIRV limit.2

Throw Weight. The limit of 190 MIRVed MLBMs will essentially freeze the Soviet MLBM modernization program since about 190 MLBM silos will have completed conversion or be under conversion to the SS–18 configuration by early fall. This could set the stage for a SALT THREE agreement in which the Soviets agree to tear down the remaining unconverted SS–9 silos and possibly some of the converted SS–18’s.

Mobile ICBMs. A ban on mobile ICBM deployment for two years would clearly have no impact on the current US M–X development program. However, it could bias Congressional attitudes toward continued funding of the M–X since support for the program is currently somewhat tenuous. Loss of the M–X program at this time would be very undesirable since it would remove a major source of our SALT THREE bargaining leverage.

The two-year mobile deployment ban is unlikely to have any impact on the Soviet mobile ICBM program since they apparently don’t plan to deploy the current model of the SS–X–16 in a mobile mode. The first flight tests of a new model of the 16 and a new larger solid-fuel ICBM, either of which could be the Soviet mobile ICBM, are expected sometime this year. However, the proposed deployment ban will ensure that the Soviets do not take the step of deploying a mobile ICBM, a step which could make a total ban on mobile ICBMs (such as that contained in our comprehensive Moscow proposal) difficult to achieve.

Since our mobile M–X would not be ready for deployment before 1985 and since the Soviets offered to ban mobile ICBM deployment through 1985, extension of this new Interim Agreement well beyond 1979 could be acceptable from the mobile ICBM standpoint. However, without any restrictions on improvements to existing ICBMs, US silo-based ICBM survivability could start to degrade in the early 1980’s. Thus, we might want the right to deploy mobile ICBMs after 1985.

ICBM Modernization. The ban on testing of new MIRVed ICBMs will have no impact on US programs since the M–X is not scheduled to enter testing until 1981. Similarly, it would not have a major impact on the Soviets even though they are expected to start testing of a new solid-fueled ICBM later this year and two new liquid-fueled ICBMs (one light, one heavy) in 1978 or 1979. The reason for this lack of impact is that the missiles could easily be tested with single RVs or as MRVs (multiple RVs without independent targeting) to escape the ban on [Page 706] testing new MIRVed ICBMs. In fact, the first five tests of the SS–17 and first nine tests of the SS–18 were unMIRVed. Permitting MRV tests also raises some verification problems. This argues strongly for dropping the “MIRVed” criterion in the proposed testing ban in which case the impact on the Soviet ICBM R&D program would be substantial.3

Extension of the two-year agreement beyond 1979 could have a major impact on the momentum of the Soviet ICBM modernization program, even if they could test new unMIRVed ICBMs.

ALCMs. The proposed ban on ALCMs over 2500 km on heavy bombers and the 250 limit on platforms would have no impact on the US ALCM program for the period through October 1979. Even if extended beyond 1979, the 2500 km range limit would only require a small decrease in the ALCM B design range (currently 2800 km—the ALCM A range is 1500 km). Similarly, extension of the 250 platform limit beyond 1979 would have little impact since only the 270 B–52G/H’s are currently serious candidates for long-range ALCM deployment.

The 600 km limit on ALCMs on aircraft other than heavy bombers would not have any impact on US programs for the period through October 1979 (although it would restrict air-launched cruise missile tests beyond 600 km to B–52’s or B–1’s). If the agreement is extended, this range limit would eventually constrain certain potential theater applications which may be of interest in the late 1980’s. A 600 km limit on ALCMs on aircraft other than heavy bombers would not impact on the Soviets for the period through 1979. However, in the long term, it would provide the desired constraint on Backfire intercontinental capability.

SLCMs and GLCMs. To date, the longest SLCM/GLCM test has been to a range of about 1500 km (although the test platform was an aircraft). A 600 km SLCM/GLCM testing limit would significantly impact on the planned test program, since virtually all the roughly 80 tests planned for the next two and one half years would be to ranges in excess of 600 km. Restricting these tests to 600 km would not constrain verification of the missile’s maximum range capability (which is already complete) but would limit the ability to fully test the guidance and terrain following systems. The overall impact would probably be to delay system IOC (currently 1980) by at most a year.

In light of the above situation, extension beyond 1979 could make the SLCM/GLCM limits much more attractive to the Soviets.

Backfire. By October of 1979, the Soviets will only have produced about 180 Backfires. As a consequence, the proposed 250 limit on Back [Page 707] fire would not impact the production program unless it were extended well beyond 1979. (The 250 production figure will be reached in the fall of 1981.)4

The proposed Backfire collateral constraints are:

—A ban on training with intercontinental bomber forces.

—A ban on training with the tankers from the intercontinental bomber forces or tankers of comparable capability.

—A ban on utilization of bases north of 63° N. latitude.

—A ban on improvements in range/payload capability.

—A ban on equipping Backfires with ALCMs over 600 km.

These constraints should severely restrict the potential utilization of the Backfire in an intercontinental role, although the tanker restriction does have a loophole in that it would still permit tankers of substantial capacity. Such tankers could probably be utilized to give the Backfire some two-way intercontinental capability; thus a complete ban on Backfire tankers may be preferable.

With the exception of the 63° N. latitude basing restriction, none of the proposed constraints would severely restrict planned employment of the Backfire force. Since the Soviets currently stage naval aviation Backfires and other medium bombers through a base on the Kola Peninsula (about 66° N. latitude), the proposed basing restriction would severely restrict Backfire’s utilization as a naval weapon system in the Norwegian Sea and North Atlantic. Since this is not our intention and is certain to meet strong Soviet objection, it might be preferable to restrict basing to 63° N. (or possibly even 60° N.) but permit staging through a single naval air base at higher latitude.

Observations on the Relative Impact of the New SALT TWO Concept

A major difference between the comprehensive Moscow proposal and the new concept is the change in the impact on the Soviet ICBM modernization program. Whereas the comprehensive proposal stopped this modernization program in its tracks, the new concept would place numerical constraints only on the MLBM modernization program and more importantly would permit improvements to existing ICBMs and unlimited testing which could give them a counterforce capability. However, the commitment to freeze ICBM modernization in SALT THREE could lead to restoration of the impact of the comprehensive agreement.

A second significant change is the reduced range limit placed on SLCMs and GLCMs. This change will impact sharply on our own cruise missile testing program as well as on the cruise missile interests [Page 708] of our NATO allies who will be concerned about extension of the limits and prejudicing the cruise missile outcome in SALT THREE.

Finally, the apparent linkage between heavy bombers equipped with long-range ALCMs and the Backfire will have the effect of more sharply identifying the Backfire as a strategic system not included in the aggregate—which may not be in our interest in the ratification proceedings.

From the Soviets’ perspective, the most important features of the new concept will probably be the prejudicial nature of the numerical limits on Backfire and the lack of significant restrictions on the number of heavy bombers equipped with long-range ALCMs. They will probably recognize that the MIRVed ICBM testing restrictions in this proposal will not have a significant impact on their new programs, at least through 1979. They may even view extension of these restrictions as in their interest since it would kill the M–X program while they would be free to improve their SS–17, 18, and 19.

Possible Variations on the New Proposal

As indicated above, we believe the ban on testing “new MIRVed ICBMs” should be changed to a ban on testing “new ICBMs.” In addition, the loophole on Backfire tankers should be closed and we should consider permitting Backfire staging (but not basing) through a single naval air base above 63° N. latitude.

An additional variation that we would suggest making would be to replace the current linkage between Backfire and heavy bombers with long-range ALCMs by a linkage between MLBMs and such heavy bombers. The basis of this linkage would be to tie the largest throw weight systems on the US side to the largest throw weight systems on the Soviet side. This linkage would not have the political disadvantage of linking Backfire explicitly with a strategic system, and would balance the MLBM asymmetry favoring the Soviets with a heavy bomber/long-range ALCM asymmetry for the United States. A limit of 200 would be of interest.5

Consideration might also be given to extending the agreement for another year. This would not have a substantial impact, would permit unhurried ratification, and allow the time which may be needed for negotiation of SALT THREE.6

Summary Assessment

In sum, the proposal does not appear to compromise any of our own or our allies’ most important near-term interests. At the same time, [Page 709] it should be more attractive to the Soviets and set the stage for a more comprehensive SALT THREE agreement.


Washington, undated.

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Expiration Date December 1985 December 1985 December 1985 for aggregate and MIRV level; October 19797 for other Measures.
Aggregate 2400 1800–2000 2200
MIRV Level 1320 1100–1200
550 MIRVed ICBMs
Throw Weight Limit of 150 MLBMs Limit of 190 MIRVed MLBMs
Mobile ICBMs Ban Deployment Ban Development, Testing, and Deployment Ban Deployment
ICBM Modernization Ban Modifications of Existing ICBMs and Limit Flight Tests to 6 Per Year; Ban Testing and Deployment of New ICBMs Ban Testing and Deployment of New MIRVed ICBMs
SLBM Modernization Limit Flight Tests of Existing and New SLBMs to 6 Per Year
ALCMs on Heavy Bombers Ban Over 2500 km; Count Platforms in 1320 Ban Over 2500 km Ban Over 2500 km; Limit of 250 Platforms
ALCMs on Aircraft Other Than Heavy Bombers Ban Over 600 km Ban Over 600 km Ban Over 600 km
SLCMs and GLCMs Ban Over 600 km Ban Over 2500 km Ban Testing Over 600 km; Ban Deployment of SLCMs/GLCMs with Ranges Over 600 km
Backfire No Deployment as a Strategic Weapon; Collateral Constraints Production Limit of 250; No Deployment as a Strategic Weapon; Collateral Constraints
Specific Commitments to Follow-on Negotiations None Substantial Reductions Plus ICBM Modernization Freeze
  1. Source: Carter Library, National Security Affairs, Brzezinski Material, Subject File, Box 52, SALT: 3–4/77. Top Secret; Sensitive. Brzezinski sent this paper to Carter under cover of an April 30 memorandum, noting that he had his “systems analysis people do a short analysis of the new SALT TWO concept.” He also included a table comparing the new proposal to the comprehensive proposal and the current Soviet position, which is printed as an attachment below. Carter wrote on this covering memorandum: “Good analysis. J.” (Ibid.)
  2. Carter underlined “7th Trident submarine.”
  3. Carter wrote “Ban testing new ICBM’s” in the margin next to this paragraph.
  4. Carter underlined “250” and “1981.”
  5. Carter underlined the last sentence of this paragraph.
  6. Carter wrote “3 years” in the margin next to this paragraph.
  7. Carter underlined “October 1979” and wrote “Δ to 1980” in the margin.