HISTORY OF STRENGTH ESTIMATES OF VIET CONG IRREGULARS

• Document Type: SPECIALCOLLECTION
• Collection: Tet Declassified
• Document Number (FOIA) /ESDN (CREST): 06787111
• Release Decision: RIPPUB
• Original Classification: U
• Document Page Count: 3
• Document Creation Date: April 27, 2019
• Document Release Date: April 30, 2019
• Publication Date: March 28, 1968

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MEMORANDUM FOR THE RECORD:
SUBJECT: History of Strength Estimates of Viet Cong Irregulars
28 March 1968
1. Strength estimates of irregulars prior to 1962 are unavailable.
(COI 6--t7t)
2. In mid-1962 MACV estimated there werelf25,0Q0jViet Cong
irregulars in South Vietnam, The estimate was based on extranolations
3. Early in 1963 the estimate was reduced to 80-100,000, and
before the end of the year was reduced again to 60-80,000. The stated
justification for the reductions was two-fold:
a. The high level of casualties inflicted on the Viet Cong in
1962 and 1963, and
b. The narrowing of the VietCong recruiting badvcaused by
the strategic hamlet program.
4. An unstated reason for the decline was that MAN was compen-
sating for numbers it was then adding to the Main and Local Forces.
With the lowering of the irregular figure, the OB showed a net decline,
despite strength rises in the Main and Local Forces,
5.- After the collapse of the Diem government on 1 November 1963,
and the ensuing political chaos, MACV revised its holdings in 1964
upwards to 100-120,000.
6. In late 1964, MACV combined its Order of Battle with that of
the South Vietnamese Army (ARVN), accepting the latter's figures for
irregulars, In early 1965 MACV's Order of Battle, using ARVN's estimate,
listed 103,573 as the number of irregulars, including 34,315 guerrillas,
35,661 militiamen, and 33,597 were identified as belonging to the
secret self defense."*
*A COSVN document, apparently written in April 1965, suggested that
the number of guerillas and militiamen at that time was between
200,000 and 225,000. The document did not break them down by type.
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7. The official irregular figure continued at 103,573 until May
1966 when ARVN surfaced a new irregular OB.*-, MAN adopted ARVN's new
number, 112,760. The number was not broken down by component.
8. On 8 September 1966, a "draft working paper" based on captured
documents which suggested that the irregular OB should be doubled at
least, was issued -- after considerable hesitation -- by the CIA and
passed shortly thereafter to MACV. The paper induced MACV to review
its irregular holdings. In October, MACV sent intelligence requirements
to the provinces, asking them to come up with new irregular estimates.
9. At the Honolulu Intelligence Conference of 6-12 February 1967,
MACV indicated that reports from the provinces suggested there were then
198,000 irregulars in South Vietnam, including some 65,000-odd guerrillas.**
CIA representatives attending the conference gave MACV a draft CIA study
never published subsequently.-- suggesting there were 250-300,000
irregulars in South Vietnam.
109. Officially, MACV continued to hold ARVN's May 1966 number of
112,760. This number was challenged in July 1967 during discussions of
preliminary drafts of National Intelligence Estimate 14.3-67.
11. As a result of controversies engendered by the challenge to the
irregular figure (and other OB numbers), a conference was convened in
Saigon in September 1967, attended by representatives of MACV, DIA, CIA,
and the State Department. The conference, CIA officially concurring,
agreed to the following propositions vis-a-vis irr9gulars:
a. That the number of guerrillas was 84,000.
b. That the self-defense and secret self-defense forces e
dropped from the OB.
12. Since then, the OB, which dropped the self-defense and secret
self-defense forces, has carried the following guerrilla strengths:
a. 81,390 in the 31 October 1967 OS.
b. 71,700 in the 31 December 1967 OB.
c. 72,605 in the 31 January 1968 U.
d. 47,470 in the 29 February 1968 OS.
*A COSVN-level document apparently written in April 1966 indicated
the number of irregulars had risen to 330,000, including 180,000
guer4.11as and 150,000 militiamen.
.**A high-level Viet Cong document of February 1967 suggested that
there were then 150,000 guerrillas. The document did not list the
number of militia.
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13. Thus in the four-month period between 31 October 1967 and
29 FebrupT 1968, the number of guerrillas has declined 33,830, or about
42 percent. The stated reasons for the reductions were:
a. The high level of casualties inflicted on the Viet Cong
during the period (particularly during the Tet offensive), and
b. The large-scale upgrading of guerrillas into higher level
units.
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SANIBEL A. ADAMS
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