69. Memorandum From Secretary of Defense Brown to President Carter1
SUBJECT
- The Diminishing U.S. Lead in Total Number of Strategic Warheads
These are some thoughts to bear in mind as we think about the future strategic balance and about the importance of SALT limits on RV fractionation.
Our projected lead throughout the 1980s in total numbers of strategic warheads is based on intelligence estimates that assume very little increased fractionation by the Soviets. You should realize that there are few data to support that assumption. In the absence of SALT fractionation limits, it is quite possible the Soviets may deploy, or at least test, modifications of ICBMs and SLBMs with much higher payload fractionations than those of current systems. Even with SALT limits they can make considerable progress in this direction. They might do so (1) in order to eliminate our lead in the perceptually important number of warheads, (2) because of a “technological imperative” to go beyond what they have now, or (3) to make MAP less attractive by forcing it to absorb more attackers—or for a combination of these. Looking at past estimates, one sees that until testing began the intelligence community projected the number of RVs on follow-on ICBMs (those we now call SS–17, SS–18, and SS–19) to be generally lower than now [Page 301] accepted (3 predicted, 4 actual; 6 predicted, 10 actual; 3 predicted, 6 actual; respectively). Therefore, the number of Soviet missile warheads could increase substantially by 1985.
The United States at present has about a 2:1 advantage in total strategic warheads [less than 1 line not declassified]. The NIE Best Estimate (assuming a SALT II agreement with a 1,200 MIRV limit) projects a U.S. advantage of about 1.5:1 (roughly [less than 1 line not declassified]) by 1985. This estimate assumes an SS–NX–18 and Typhoon missile with three and four RVs, respectively. The Soviets recently demonstrated a potential capability to deploy seven RVs on the SS–NX–18: at least two tests released four RVs and simulated three additional releases. With seven RVs per SS–NX–18 and Typhoon missile the Soviets would reduce our advantage to about 1.3:1 in 1985. Putting the situation in another way, our lead could be eliminated entirely if, for example, the Soviets increased the number of RVs on the SS–NX–18 and Typhoon missile to 14, or on the SS–19 from six to 16. These fractionation levels would probably be feasible on follow-ons to existing missiles and on the new Typhoon SLBM.
The ban on increasing numbers of RVs on existing types which we have proposed in SALT would make this erosion of our lead far more difficult because it would prevent fractionation of the payloads of existing types. However, even our current SALT fractionation proposal (limiting new ICBMs to 10 RVs and new SLBMs to 14 and freezing fractionation of current ICBMs and SLBMs) still permits the Soviets eventually to catch up with us in warhead numbers by replacing all existing systems with permitted new types with the maximum permitted RVs (e.g., by increasing the SS–19, SS–NX–18 and Typhoon to 10 RVs). Soviet tests of existing systems with more RVs before signature would pose a problem (though formally our position takes the pre-April 15, 1978 level as the base).
We should therefore recognize that our lead in strategic warheads could largely dissipate by 1985, or even disappear altogether if the Soviets chose that course. This capability could be delayed by SALT but is unlikely to be blocked entirely. Our ability to claim future strategic equivalence on the basis that their lead in throw weight is offset by our lead in warhead numbers, is thus fragile.
We do, however, have several options available to counter a Soviet push to close the gap in numbers of warheads. The Cruise Missile Carrier (CMC) program provides an option for a major and rapid increase in strategic capability. For example, a deployment of 100 CMCs. [2 lines not declassified] This deployment level could be achieved by FY 1987 with an orderly program, and earlier if extraordinary effort is deemed necessary. The current U.S. SALT position would count each CMC as one in the 1320 aggregate. The Soviets have proposed a limit of 20 cruise [Page 302] missiles per aircraft. As you are aware, Secretary Vance recently presented our position that there could be no limitations on the number of cruise missiles per CMC as long as there are no limitations on air defenses.
Another alternative is the Ground-Launched Cruise Missile (GLCM) for which we currently have very tentative plans for initial deployment in 1982. Those plans involve deployment of 500 to 600 missiles, each with a variable yield warhead up to [less than 1 line not declassified]. If we have to respond quickly to a rapid Soviet buildup in total RVs, this program, or a similar one involving surface-ship launch, could be quickly and greatly expanded. The production rate can be rapidly multiplied, and is not restricted by SALT after the Protocol expires (though it could pose other political problems).
In sum, we must be aware that the Soviets could largely negate our lead in warheads by 1985. However, there are SALT-permitted options available to maintain our lead in strategic warheads, if we so desire.
- Source: National Archives, RG 218, Official Records of the Chairman of the Joint Chiefs of Staff Jones, Box 60, SecDef Memo Jul 78. Top Secret. Copies were sent to Vance, Brzezinski, Brown, Seignious, and Turner.↩