Foreign Relations of the United States, 1969–1976, Volume VII, Vietnam, July 1970–January 1972

166. Memorandum From K. Wayne Smith of the National Security Council Staff to the President’s Assistant for National Security Affairs (Kissinger)¹

Washington, March 25, 1971.

SUBJECT

• South Laos/Lam Son Logistics Analysis

Introduction

CIA has produced a first-rate analysis of the logistics situation in South Laos (at Tab B).² If you disregard the rhetoric on enemy intentions (probably Carver’s) Walsh’s analysts have done a superb job. (Incidentally Walsh has consistently refused to allow his otherwise willing analysts to be more quantitative. In this case your specific demands, fully endorsed by Helms, could not be denied.) I think you should go out of your way to compliment this CIA effort.

DIA has submitted a classic intelligence estimate (at Tab C)³ throwing in every bit of information available but without any analytical structure. Where DIA provides comparable data I take it into account. Particularly on throughput data, DIA and CIA have stated their positions fully. But DIA does not appear to have grasped the concept of the model you put forward, a major virtue of which is that it can be solved without throughput data.

It is interesting to note that while the CIA calculations are done on a slightly different basis than ours, the results are generally the same. Their findings have led CIA to conclude that this dry season’s logistics effort:

“. . . will be adequate for the Communists to sustain military activity at the low levels observed during 1970 [the “hot war” is at last defined].

“[It] will not permit the Communists to build up any significant volume of stockpiles and will make it imperative that their next logistic offensive get off to an extremely early start next dry season.⁴

“In sum, North Vietnam’s logistic position over the past year has become greatly complicated. Far from enjoying a wide range of logistic options to support alternative strategies, Hanoi appears tied, for 1971 at least, to a continuation of the low-profile war fought in 1970. While the enemy’s logistic situation does not preclude an occasional high point of combat activity in either South Vietnam or Cambodia, major sustained warfare seems definitely to be ruled out.”

Strategy for WSAG Meeting

Your talking points focus first on obtaining a consensus on the incremental demands on the Trail system this year compared with a year ago.⁵

Next, you attempt to get the intelligence community to agree on input levels thus far this year and to lay out what the enemy can do logistically for the balance of the dry season and into the wet season.

Third, you raise the throughput estimate issues and the alternative CIA and DIA views to see how they confirm the results obtained from the incremental input analysis.

Fourth, focussing again on the incremental input requirement this year versus last year and weighing this year’s total requirement against his possible efforts for the balance of the dry season, you seek to obtain agreement on the conclusions the logistics data will support. (These conclusions are those in CIA’s memorandum and are very similar to those we came to a week ago.)

Comparative Analysis of CIA, DIA, and NSC Estimates of Incremental Demands on Logistic System This Year

The CIA, DIA, and NSC estimates of 1971 increments are summarized in the following table:

Estimates of Increased Input Requirements for 1970–71 Versus 1969–70 Dry Seasons

	CIA	NSC	DIA
1. Sihanoukville	5,520–8,160	21,000	no estimate
2. Increased Non-Combat Consumption to Support Enlarged South Laos Force	7,900
3. Lam Son Caches Destroyed or Captured	3,650	2,118	3,500–4,800
4. Combat Consumption to Cope with Lam Son	3,070	900	2,300–2,600
5. 1971 Bombing Increment over 1970	0	6,000	no estimate
	20,140–22,780	30,018

The major difference between the NSC and CIA estimates is that NSC estimates that about 8,000 more tons are required to replace Sihanoukville.

Two different methodologies are used. NSC applied a conservative trail mix factor (25% ordnance) to the ordnance flow through Sihanoukville that could be reasonably attributed to 1970 (5,000 tons). This method of calculation necessarily incorporates the food and POL input increments to move the increased ordnance that in 1969–70 passed through Sihanoukville.

CIA does a more detailed item-by-item analysis breaking out the consumption requirement for the increased force in South Laos in a separate calculation.

Their approach may have produced a low estimate because:

• —they use a figure of 10,000 for the increased force in South Laos in early 1971 versus early 1970. This appears to be low by CIA’s own estimates. CIA Memo 71–32 dated February, 1971⁶ states, “During 1970 the NVA bolstered its force structure in southern Laos by 20,000 men concentrated heavily in the Tchepone area.”
• —their methodology does not explicitly account for the incremental POL requirement to move the Sihanoukville increment down the Trail. Our intercepts show that at or near the top of the Trail in early 1971 the mix was 20% ordnance, 60% food, 15% POL and 5% other supplies.

You should point out the NSC method of calculation which tends to suggest items 1 and 2 of CIA’s analysis are underestimated.

You should also ask whether DIA and CIA agree on the consumption figures used for enemy forces in South Vietnam and Laos. I believe there is a real possibility that the intelligence community has underestimated badly external logistics requirements for enemy forces.

Such underestimates are suggested by the extent to which CIA believed the enemy did not need Sihanoukville, a belief that may have moved CIA to its mistaken estimate. Page 6 of the CIA memo acknowledges that between 1966 and 1970 the enemy perceived its requirements to be “1.5 times greater than our estimates of current ordnance requirements.” Whenever the enemy claims it has more control in the countryside than GVN data show, CIA agrees with them. Why do they discount the enemy’s estimate of his own logistics needs? One wonders if GVN pacification progress has made the enemy more dependent on external supplies than in the past and whether our estimates reflect an increasing reliance on external sources of supplies.

CIA is correct on items 3 and 4 because they used more recent and complete estimates. However, the North Vietnamese are saying (in Paris to Burchett,⁷ for example) that while ARVN destroyed some caches, large quantities of U.S. air dropped supplies have fallen into NVA hands. DIA should be asked for its view of this assessment.

Finally CIA’s estimate does not include an increment to offset incremental bombing effectiveness this year. The NSC estimate was 6,000 tons. Should this be cranked in. On the other hand, CIA uses a 25% loss factor to bombing on the Trail. You might ask what evidence there is to support such an estimate.

Once the differences are resolved, an agreed increment will result. However, even using the 20,000 to 30,000 range bounded by the NSC and CIA models, the next step in the analysis can be taken.

Calculating the Total Input for 1970–1971

CIA calculates the normal input requirement for the Panhandle to be 54,000 tons. NSC used last year’s input figure of 60,000 as a proxy for the normal requirement. You might ask CIA how the estimated normal requirement of 54,000 tons compares with last year’s input and what conclusions one draws from any difference.

Below are the estimates for total input requirements this dry season to sustain 1970 rates of activity.

	CIA	NSC
“normal” (1969–70)	54,000	60,000
increment (1970–1971)	20,140–22,780	30,018
Total (1970–1971)	74,140–76,780	90,018

Comparing Total Input Required to Total Capacity

If we know the range of the total input estimates (74,000 to 90,000), this can be compared with possible throughput in 1970–1971. Assuming the enemy continues to move supplies well into May, CIA estimates total input at between a minimum of 70,000 tons and a maximum of 89,000 tons depending on whether one includes pipeline and waterway capacities.

This range of estimates, which can be updated as additional data come in, is probably acceptable to DIA (our estimate was 74,000 tons) although DIA should be asked.

Estimate of Level of Activity

Conclusions can be drawn on the basis of input data alone. Both CIA and DIA provide their throughput estimates. DIA’s is a guess. CIA’s is based on a credible model that they might be asked to explain. But the data are soft and I doubt whether throughput data should be used except as an adjunct to input data. It could tell us if conclusions drawn from input data are way off the mark.

Deriving conclusions from the input data is simple. CIA projects total demand to be 74,140 to 76,780 compared with a total capacity of 70,000 (minimum) to 89,000 (maximum). One can safely draw the conclusions CIA drew (spelled out at the beginning of this memorandum) from these data. The basis for these conclusions will probably be strengthened by refinements of CIA’s data because they should serve to raise total requirements closer to even maximum capacity.

I am bothered, however, by CIA’s tautological reasoning on enemy intentions. From their study of enemy intentions, CIA expects a protracted war and views the results of their analysis as a confirmation of their expectations. This is wrong. What the analysis says, as indeed the CIA memorandum tells us, is that the enemy has little choice in 1971.

Addendum

We were told by CIA that they sought to get DIA on board for a joint analysis along the lines you requested, but DIA refused.

Your talking points will be sent over later this evening.

1. Source: National Archives, Nixon Presidential Materials, NSC Files, NSC Institutional Files (H-Files), Box H–80, WSAG Meetings, Lam Son 3–26–71. Top Secret. Sent for information.
2. Attached but not printed is a March 25 covering memorandum from Helms to Kissinger and Intelligence Memorandum SC04513/71, March 1971, “The Impact of Logistics Factors on NVA Offensive Capabilities During 1971.”
3. Attached but not printed is a memorandum from Packard to Kissinger, March 25, with a report entitled, “The Situation and Outlook for Indochina.”
4. Brackets are in the original.
5. Kissinger’s talking points are in the National Archives, Nixon Presidential Materials, NSC Files, NSC Institutional Files (H-Files), Box H–80, WSAG Meetings, Lam Son 3–26–71.
6. Not found.
7. As reported in CIA Intelligence Information Cable TDCS–315/01185–71, March 8, which Smith forwarded to Kissinger under a March 25 covering memorandum. (National Archives, Nixon Presidential Materials, NSC Files, Box 153, Vietnam Country Files, Vietnam, 11 Feb 1971–28 March 1971) Wilfred Burchett was a left-wing journalist associated with Communist causes and close to leading North Vietnamese Communists.