302. Note from Kaysen to Bundy, October 251

[Facsimile Page 1]


The attached is a comment on McNamara’s Strategic Forces Memo in its own terms. I have given a copy to Spurgeon Keeny and, informally, to Alain Enthoven.

In reading this comment there are a number of things to bear in mind: (1) The loose connection between the argument and the numbers might indicate that it is McNamara’s judgment that these numbers are the minimum the Services will accept. This is one way to interpret constancy of numbers in relation to changing arguments. (2) The Budget provides for a decision to procure only 50 of the 250 Minutemen additional to those already authorized which it sets as the force goal. A decision on the remaining 200 is yet to be made. The change downward of this year’s over last year’s force goal figure—although achieved mainly by faster retirements of Atlas E and Titan 1—may signify that the present 1200 figure need not represent a final commitment.

On the disarmament side it can be argued that there might be some advantage in the smaller figure if we made it explicit to the Soviets that we were reducing our force goals. Absent such communication, variation up or down of the magnitudes here involved probably would not affect the Soviets much.

On the other side it can be said that the DOD presentation concentrates rather narrowly on Soviet forces. If we look as far ahead as 1969 we should be considering the contingency of other significant forces. Whether an increased general reserve is best achieved in the form of Minutemen—which might have some difficulty in reaching certain targets—or in the form of more SSBN, is another question.

[Facsimile Page 2]

For all these reasons, especially the smallness of the saving achievable in FY 65, and the undesirability of presenting a target to Goldwaterism on this issue, I am content to let my argument rest where it is. I suspect that Enthoven’s response to it will be to change the rationale of the DOD figures without changing the figures.

[Facsimile Page 3] [Typeset Page 1355]


(August 31, 1963)

(1) The DOD paper examines the strategic retaliatory force in a somewhat different framework of argument than that of the previous two years. Our 1969 strategic forces other than Minutemen are assumed fixed, and the choice among 3 Minutemen forces is considered: 1200 (of which 920 are improved); 950, and some larger force than 1200. The conclusion is that a force of 1200 Minutemen is adequate; a larger force has little extra usable military power, and the smaller force does not give an appropriate degree of assurance against the possibility of highly unfavorable contingencies.

(2) The 1200 man Minutemen force goal for FY 69 is justified in terms of the concept of “assured destruction”, defined as a high degree of assurance that, under pessimistic assumptions and adverse conditions, the programmed force can destroy a sufficient fraction of Soviet industrial capacity and kill a sufficient fraction of the Soviet population to put beyond question a deliberate nuclear first strike on the U.S. as a rationale Soviet policy.

(3) Beyond a capability to achieve assured destruction, we might seek two successively further goals: damaging limiting capability, and full first [Facsimile Page 4] strike capability. As far as first strike capability, the paper argues that by the end FY 1969, Soviet hardened and submarine launched missiles will be sufficient in number so that even a very large increase in our strategic forces (to 1950 Minutemen) combined with a large increase in active and passive defenses ($80 billion worth), could not prevent the Soviets from causing an unacceptably high level of U.S. casualties; i.e.: 30 million. This would be the case even if the Soviets built the level of forces we now expect. However, so large an increase in our own offensive and defensive programs could be expected to provoke a significant Soviet response, and further increase the expected level of U.S. casualties.

The increase in the damage limiting capacity that is achieved by extra Minutemen beyond the programmed 1200 is so small that the additional forces are not justified. However, the gain in this respect from the force increase between 950 and 1200 is judged worth-while. The figures summarizing these arguments are shown in Tables 1 and 2 which follow.

[Facsimile Page 5] [Typeset Page 1356]


U.S. Second Strike Capabilities, FY 1969 (Expected Results With Alternative U.S. Forces vs. Medium Soviet Threat)
Force I Force II Force III
(Incl. 950 MM) (Incl. 1200 MM) (Incl. 1400 MM)
(a) (b) (a) (b) (a) (b)
Missiles only Total Force incl. A/C
Urban Industrial Targets
Number 215 215 215 215 215 215
Fatalities (millions) 80 83 90
IndustrialCapacity (%) 50 50 50 50 50 50
High Urgency
Number 433 520 545 649 584 678
% of total 50 60 63 75 68 79
Other Military
Number 268 34 367 38 37
% of total −31 4 43 S 44
[Facsimile Page 6]


U.S. Second Strike Capabilities Against the Soviets, FY 1969
Number of Minutemen Expected Factors Pessimistic Factors
(a) (b) (a) (b)
% Fatalities %Industrial Capacity
0 47 57 17 30
600 59 70 18 32
950 68 82 25 45
1200 71 88 30 51
1400 73 90 33 55
[Facsimile Page 7]

(4) The arguments used to support the choice of 1200 Minutemen are not such as to justify that figure with any precision. With small changes of emphasis, the same assignments could be used to justify 950 Minutemen.

[Typeset Page 1357]

How much “assurance” of how much destruction is enough? The difference between 68% and 71% of Soviet population killed under the expected conditions of Soviet defensive capability and U.S. operational efficiency clearly does not justify an increased force. Does the difference between 25% and 30% casualties under unfavorable assumptions? (See Table 2). The unfavorable assumptions on Soviet defenses, (a nation-wide fallout program plus ABM protection for 10–15 cities); Soviet forces (top instead of middle of range of predicted future size; improved reliability, decreased CEP); U.S. forces (decreased reliability and survivability) form a quite unlikely constellation indeed. Each contingency is described as the worst consistent with the available evidence. But if each “worst case” is assumed to be as likely as the expected outcome—an assumption that gives little credit to our estimates—for these six factors (treating fallout protection plus AIBN deployment as one factor), then the combination of unfavorable outcomes has a less than 2% probability (1 in 64). How much insurance against this unlikely contingency should we buy?

It is clear that the smaller force would be just as effective as the larger one in causing the Soviets to harden and disperse their own missile [Facsimile Page 8] forces. With a reduction in our Minutemen forces from 1200 to 950, the total ratio of U.S. ballistic missiles to Soviet missile launchers would change from 1967 to 1100 to 1726 to 1100. Certainly this difference would not justify the Soviet decision to stop hardening.

In terms of damaging limiting capability, the difference between 1200 and 950 is fairly small. Under favorable assumptions for us of adequate fallout protection and enough warning time to enable us to hit the Soviet striking force, the 250 extra Minutemen would reduce U.S. casualties by some 3½ million from 84.5 to 81 million. As for counter-force capability, the proposed force would permit attack on 865 time-sensitive targets (assigning defense suppression entirely to Hound Dogs on alert B–52’s). With only 950 Minutemen, this number would be reduced to 685; enough to cover all Soviet missile launchers, bomber bases and sub-bases, but omit fighter bases and targets in the satellites.

The difference between the two programs, namely 1200 (920 improved) and 950, (with approximately the same proportion improved) would be about a billion dollars over the five year period. The saving in FY 65 would, however, be only the $50 million to be spent in FY 65 on the procurement of the 50 additional missiles authorized for procurement.

(5) The comparison between the missile forces proposed in successive budgets, and the arguments used to support them is instructive. In 1961, [Facsimile Page 9] the strategic force goal (for 1967) was justified in terms of a controlled counter-force capability, somewhat short, however, of a full-[Typeset Page 1358]first strike. In 1962, counter-force was de-emphasized, in favor of our ability to limit damage to U.S. should deterrence fail. This year, even damage limitation is accorded relatively small emphasis, and assured destruction becomes the keystone of the argument. Yet the changes in the relation of our proposed forces to our estimate of Soviet forces and other major elements in the Soviet target system, as shown in Table 3, do not reflect this change in rationale. Indeed, the little shift there has been is in the opposite direction. Soviet targets have been declining in number while our force goals have remained essentially constant.

[Facsimile Page 10]


Proposed U.S. Missile Forces and Estimates of Selected Elements in the Soviet Target System
1961 for 1967 1962 for 1968 1963 for 1969
Total U.S. Ballistic Missiles (ICBM & SLBM) 1987 2163 1972
Total Soviet target list 1775 1510 1540
Total Soviet Missile launchers (ICBM, IRBM, SLBM) 1400 1548 1342
Total Soviet high urgency targets 1225 848 750
Total Soviet fixed missile targets 925 612 550
  1. Provides comments on McNamara’s strategic forces memorandum. Top Secret. 10 pp. Johnson Library, National Security File, Agency File, Def Bud 65.