131. Memorandum From the President’s Assistant for National Security Affairs (Brzezinski) to President Carter1
SUBJECT
- PRC on M–X Basing (U)
A PRC meeting was held last Friday2 to review the M–X basing decision. The meeting opened with a summary of the underlying issues, a brief review of the main features of both sides’ ongoing strategic modernization programs, and the presentation of the five ICBM modernization options that DOD has been studying: (1) a baseline option with minimal modernization; (2) an option adding MPS/M–X to the baseline for an additional $32B thru FY 2000; (3) an option adding missiles on trucks for $26B; (4) an option adding 100 M–X in STOL aircraft and 100 M–X in silos for $35B; and finally, (5) an option putting Trident II missiles in silos and submarines, and increasing the baseline cruise missile carrier purchase by 100 at a total cost of $37B. (S)
After a short examination of the relative cost effectiveness of each option (i.e., life cycle costs/surviving RV in a “bolt from the blue” attack) that showed Option 5 to be best, 2 second, 4 third and Option 3 tied with 1 because truck mobiles cannot survive without strategic warning, the discussion turned to a comparison of the qualitative characteristics of each option. The following points were made:
Option 2 is the JCS strong and unanimous choice: it solves the U.S. alert ICBM vulnerability problem but puts Soviet ICBMs at risk—thus providing leverage for SALT III reductions. They argue that MPS can be expanded, or protected by ABM, if greater threats develop. (The ABM Treaty would have to be modified or terminated.) The JCS argue it can be verified using cooperative measures (e.g., on site inspection) which the Chiefs argue will be needed to achieve deep cuts in SALT III (S)
Others pointed out (1) that MPS could make future SALT reductions easier by making the percentage survivability of this ICBM force independent of the number of missiles it deploys, (2) that loss of security, particularly if we were not aware of it, would make MPS a disaster, (3) that the “breakout” problem of a Soviet MPS is not unique to MPS, (4) that MPS should be examined against threats greater than those allowed under SALT II because it won’t start deployment until 1986, [Page 608] (5) that the large number of valuable MPS aim points and the powerful first strike capability of M–X against Soviet ICBMs might reduce Soviet incentives to extend the fractionation limits of SALT II beyond 1985 and into SALT III, (6) and finally, that getting cooperative measures in SALT III needed to verify a Soviet MPS may consume U.S. bargaining leverage that might otherwise be directed toward reductions. (S)
There was little discussion of Options 3 and 4 beyond the JCS comment that without cooperative measures, Soviet truck mobiles would be more difficult to verify than MPS. Harold Brown thought that on balance U.S. security improved by a Soviet shift to truck mobile ICBMs since there lesser capability would offset verification uncertainties. (S)
The JCS argued that while Option 5, with its improved hard-target capability, would put the Soviets at equal risk, and provide a large number of surviving weapons, it did not solve the ICBM vulnerability problem. They further argued that Option 5 would have an adverse effect on SALT II ratification because it would raise some very contentious issues such as the advisability of putting more capable missiles in silos, which is strongly opposed on the Hill. Others noted that (1) given the political value of deploying the largest missile possible under SALT II, we should look at a variant of Option 5 putting M–X in silos, (2) that while putting more capable missiles in silos might decrease crisis stability, neither side could have more than limited success in any attempt at a disarming first strike, and (3) that variants of Option 5 substituting mobiles for silo deployments should be examined. Finally, several principals noted that if a common missile were used for both Navy and Air Force deployments, we could change deployment modes later if necessary. (S)
In the next PRC meeting, which will take place next week, we intend to (1) examine variations of Options 2 and 5—one variation of 5 will include truck mobiles, (2) compare the various types of risks inherent in proceeding with these options including the likely Soviet reaction and the impact on SALT bargaining, and (3) look more deeply at the question of cooperative measures. (S)
- Source: Carter Library, National Security Affairs, Brzezinski Material, Subject File, Box 56, SALT: Chronology: 3/79–5/23/79. Secret. Sent for information. Aaron initialed for Brzezinski. Carter wrote in the upper right corner: “Susan, SALT file. J.”↩
- May 4. See Document 130.↩