33. Memorandum From the President’s Assistant for National Security Affairs (Kissinger) to President Nixon1
- Implications of Soviet Multiple Reentry Vehicle (MRV) Test Program
Since last August the Soviets have been testing their SS–9 missiles with a large heavy warhead containing three separate weapons or reentry vehicles. Four tests were conducted within the USSR. Three more tests were recently conducted at longer range into the Pacific. In all of the successful tests, the impact patterns of the three weapons formed triangles of similar shapes with sides no longer than five miles. The Intelligence Community and other experts have been reviewing the data from these tests and debating their implications. The key question has been whether each of the three weapons could be specifically directed against a different Minuteman silo, thus implying that the Soviets were well on their way toward a MIRV capability.
I have been aware that there have been differing views concerning what these tests implied about future Soviet capabilities.2 Therefore, [Page 117] during the last few days, I have had a series of meetings with Dick Helms, Dave Packard and several other officials from CIA, the Defense Intelligence Agency and the Department of Defense concerning the implications of these recent Soviet tests.3
In my judgment, these implications add up to a decisive confirmation of both the Safeguard program and of your decision to continue with the U.S. MIRV test program. Though these discussions covered complex technical questions, I think you will want to be aware of the main issues. In particular, I think it is now appropriate to revise our Safeguard rationale to take account of our best current judgment about the Soviet threat.
The discussions centered around two questions:
- What are the technical characteristics of the Soviet MRV program based on tests conducted to date?
- Based on these technical data, what conclusions can we draw concerning Soviet progress toward developing a full MIRV capability?
There appears to be no significant disagreement about the demonstrated technical characteristics of the Soviet MRV program:
- —The Soviets can launch successfully a single SS–9 containing three reentry vehicles of about 5 megatons each.
- —Tests with the SS–9 missile indicate that a maximum range of 5000 nautical miles for the MRV system is clearly possible. (Some analyses indicate that even longer ranges are possible with a MRV payload.) With a 5000 mile range, the SS–9 MRV system can reach 5 out of 6 of our Minuteman complexes. (The sixth complex in Missouri can be reached by SS–9s with single 18 megaton warheads.)
- —It is estimated that the present Soviet MRV system if deployed, probably in 1970, will have about one-half mile accuracy. With such accuracy, each weapon will have a 66% probability of destroying a Minuteman silo. If accuracies improve to one quarter mile, each weapon will have a 90% probability of destroying a Minuteman silo. The most recent intelligence estimate is that such accuracies will be achieved by 1972.
- —The system the Soviets have been testing is significantly more complex than it would need to be if it were no more than a simple MRV program, that is, a program which could deploy three warheads but could not independently direct them to separate targets. Though the tests observed to date have not demonstrated the flexibility required for a MIRV system capable of attacking all of our Minuteman silos, any additional technical effort required to achieve such flexibility cannot be great compared to what the Soviets have already achieved with their system.
- —The evidence seems to indicate that at least 60–65% of our Minuteman silos could be specifically targeted with triple warheads based on the patterns we have seen to date. The remainder would, of course, be targeted with single weapons as the Soviet SS–9 program increases.
Implications of MRV Test Results
On the issue of what conclusions we can draw from these technical data, there is agreement that at the very least, the experience gained by the Soviets from testing to date is a significant step towards a MIRV development.
There is disagreement, however, our whether or not the system the Soviets have tested is in fact a MIRV. One view, held mainly in DIA and DOD, is that the Soviet system is almost certainly a MIRV, because:
- —the technical data, though not yet conclusive, are consistent with its being a MIRV, and
- —there is no other plausible explanation for the Soviet system; a simple MRV for the SS–9 would give the Soviets no advantage over a single warhead.
The opposing view, held by CIA, is that we cannot conclude now that the Soviet system is a MIRV, because:
- —the full capability has not been demonstrated in flight tests to date.
- —it would be a radical departure from normal practice if they were to deploy a weapon with the potential importance of MIRV’s without complete testing, and
- —it would be unwise to draw conclusions about Soviet programs based on our views of what is plausible for the Soviets to do, because we’ve been wrong before when using such reasoning.
In the CIA view, two technical capabilities should be demonstrated before concluding that the Soviets have a MIRV.
- —A capability to “roll” the SS–9 in flight in order to vary the directions in which the reentry vehicles are released.
- —A greater time span between the release of the first and the third reentry vehicles in order to spread them over greater distances.
(From private conversations, I gather that demonstration of just the second capability would probably convince most of the skeptics that the Soviets had a MIRV.)
I think that the significance of these considerations can be summarized as follows:
- —There is a positive technical evidence that the Soviets either have a MIRV system capable of attacking Minuteman or are making significant progress toward achieving one.
- —By 1974, when our Safeguard ABM first becomes operational, the Soviets could have been deploying MIRV’s for four years and highly accurate MIRV’s for two years.
- —Even the present multiple warhead is capable of covering at least 60–65% of our retaliatory force with multiple warheads.
- —The Soviet MRV program appears to be designed to threaten our deterrent by making it possible for the Soviets to wipe out our land-based missiles; it certainly is not designed simply to penetrate ABM defenses. The main purpose of our MIRV program, on the other hand, is to protect our deterrent by insuring that we can penetrate ABM defenses, though we must admit that the Soviets may see it differently. Whereas our Poseidon MIRV’s are 40 kilotons, a Soviet MIRV could be 5 megatons, or well over 100 times the yield of our Poseidon warheads.
In view of the importance of these conclusions, and because the three long-range Soviet MRV tests have taken place since your decision to deploy Safeguard, I have asked the CIA to have the United States Intelligence Board reassess certain aspects of the Soviet ICBM program, especially the SS–9 and multiple reentry vehicle programs.
Because we now have a better understanding of how the Soviet strategic threat is developing, I think it is important to update our rationale for the Safeguard deployment to reflect our best current judgment. Enclosed at Tab A is a Safeguard position paper which we prepared initially in early April.4 It has been updated in the light of the above discussion, principally by amplifying the statement of the Soviet threat on page 2.[Page 120]
If you approve this rationale as modified, I will send copies to Mel Laird, Bill Rogers, Herb Klein, Bryce Harlow and others who can make use of it in their efforts to win approval of the Safeguard program.5
- Source: National Archives, Nixon Presidential Materials, NSC Files, Box 845, ABM–MIRV, MIRV Test Program. Top Secret. Drafted by Lynn. A stamped note on the first page reads: “The President has seen.”↩
- See Documents 30 and 31. Kissinger recalled in his memoirs the controversy within the intelligence community about the SS–9. “Early in the Administration a school of thought developed that the triple warhead on the Soviet SS–9” was a MIRV “aimed at our Minuteman missile silos. The CIA maintained that the warheads could not be targeted independently. I leaned toward the more ominous interpretation. To clarify matters, I adopted a procedure much resented by traditionalists who jealously guarded the independence of the estimating process.” Kissinger conceded that “Helms stood his ground; he was later proved right.” (Kissinger, White House Years, p. 37)↩
- After reading a summary of a New York Times article about an “intelligence gap” that arose when CIA opponents of the ABM allegedly briefed like-minded Senators to undercut Laird’s testimony about the growing SS–9 threat, Nixon handwrote instructions to Kissinger to “(1) Give Helms unshirted hell for this! (2) We know it is part true (his Georgetown underlings). (3) Tell him to crack down. (4) Also—tell Cushman.” (Memorandum from Butterfield to Kissinger, June 2; National Archives, Nixon Presidential Materials, NSC Files, Box 844, ABM–MIRV, Sentinel ABM System, Vol. III) Kissinger and Helms met on June 2. According to Haig’s summary of the meeting, the two discussed “in considerable detail” the CIA’s activities “with respect to the strategic threat and their impact on ABM legislation.” Haig added, “You may be assured that Helms is aware of the President’s views on this matter.” (Ibid., Box 207, Agency Files, CIA, Vol. I) Nixon later instructed Kissinger, during a June 12 telephone conversation, “to call Helms and tell him he has fifteen minutes to decide which side he is on.” Minutes after telephoning Helms, Kissinger called the President, who “asked if Helms had made up his mind yet which side he is on.” Kissinger assured Nixon that Helms was “telling the truth to everyone” since there was “no evidence that [the SS–9’s warheads] can be independently targeted. K[issinger] said he thinks he has Helms on the ball.” All three transcripts are ibid., Kissinger Telephone Conversations, Chronological File.↩
- Attached but not printed.↩
- The President initialed his approval.↩