MANPOWER CONSIDERATIONS AND HANOI'S STRATEGIC OPTIONS

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP85T00875R001700010035-1
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 17
• Document Creation Date: December 22, 2016
• Document Release Date: January 28, 2010
• Sequence Number: 35
• Publication Date: May 1, 1971
• Content Type: IM

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Secret
-T/-~ ~71-oq
DIRECTORATE OF
INTELLIGENCE
Intelligence Memorandum
Manpower Considerations And Hanoi's Strategic Options
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WARNING
This document contains information affecting the national
defense of the United States, within the meaning of Title
18, sections 793 and 794, of the US Code, as amended.
Its transr, ;lion or revelation of its contents to or re-
ccipt by an unauthorized person is prohibited by law.
OPOUP I
Crdudnd iro ro,omoiit
rra dfnq and
"dndo?~fud~nn
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CENTRAL INTELLIGENCE AGENCY
Directorate of Intelligence
10 May 1971
Manpower Considerations
And Hanoi's Strategic Options
Introduction
1. This memorandum presents additional analysis
requested by the Senior Review Group on the manpower
implications of alternative US troop withdrawal
rates.
2. The analysis considers Communist manpower
requirements to support seven alternative strategies,
ranging from a continuation of the protracted war-
fare with its occasional highpoints which was
typical of 1970, to a sustained general offensive
throughout South Vietnam and Cambodia. We focus
specifically on how US withdrawals might affect
Communist manpower from three points of view:
(a) the aggregate combat force re-
quired to sustain each alternative strategy,
(b) the changes which US force with-
drawals have on friendly/enemy force ratios,
(c) the effect on enemy casualty rates.
3. In addition to measuring these three effects,
the analysis also presents estimates of enemy force
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requirements and friendly/enemy force ratios at
quarterly intervals during the period.
The Analysis
4. we estimated in our basic
analysis that the Communist forces could maintain
the protracted warfare of 1970 with its existing
force of 115,000 combat troops. We also presented
estimates of the force augmentation required to
support six alternative offensive campaigns,
assuming that the NVA force requirements to imple-
ment each strategy would be roughly equivalent to
the average maintained during 1968 and without
reference to US withdrawals. The analysis also
estimated the same requirements assuming US forces
were drawn down to a residual force of 43,400 in
mid-1972.* The force augmentations required in
either situation are shown below:
Force Requirements
(Thousand Men)
Basic US
Strategy Analysis Withdrawals
Case I 115 --
(1970 Protracted Warfare)
Case II 135 115
(MR 1)
Case III 125 129
(MR 2)
Case IV 145 129
(MR 1 & 2)
Case V 135 135
(Cambodia)
Case VI 155 135
(MR 1/Cambodia)
Case VII 175 143
(GVN/Cambodia)
An interme iate variant whereby the US residual
force is 153,000 in mid-1972 is not considered in
this analysis.
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Time-Phasing of Alternative Withdrawal Rates
5. In this section the analysis refines our
measurement of the impact of friendly troops by
time-phasing our analysis to determine enemy force
requirements between now and mid-1972. We assume
that by mid-1972 the United States will have a
force residual on the order of 50,000 troops. We
also consider the effect of the withdrawal of one
Korean division from MR 2, as well as ARVN rede-
ployments during the period. The analysis is done
in two alternative ways:
(a) friendly force withdrawals and
ARVN redeployments are made on a straight
line basis, and
(b) the force withdrawals are made on
a plausible case consistent with maintain-
ing a stronger US presence over as much of
the period as possible but still coming
close to meeting a mid-1972 target of
approximately 50,000 troops.
Alternative A
6. The time-phasing of enemy force requirements
for each strategy when withdrawals are made on a
straight-line projection are shown in Table 1.*
In this case there are no US combat forces by mid-
1972.
7. Table 1 shows among other things that the
impact of US force withdrawals has a quick effect
on enemy force requirements. By the middle of the
1971-72 dry season, for example, the force augmen-
tation required to implement the maximum strategy --
an offensive throughout South Vietnam and Cam-
bodia -- would be reduced by about 50%, from 60,000
in our basic analysis to less than 35,000.
8. The question of the withdrawal of Korean
troops is also of interest. The withdrawal of a
Korean division reduces the manpower augmentation
requirement for the maximum strategy by mid-1972
The supporting data showing Allied maneuver de-
ployments are shown in TaLZe 2.
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Enemy Combat Force Requirements -- Alternative A a/
Basic
Analysis
Jun 71
Sep 71
Dec '71
Mar 72
Jun 72
Case I
115
(1970 Protracted Warfare)
Case II 135
(MR 1)
132
128
124
120
115
Case III 125
125
124
124
124
123
(MR 2)
(126)
(127)
(128)
(129)
(129)
hrj
Case IV 145
142
137
133
129
123
(MR 1 & 2)
Case V
(143)
(140)
(137)
(134)
(129)
(Cambodia)
Case VI
(MR 1/Cambodia)
Case VII
169
158
150
1.44
137
(GVN/Cambodia)
(170)
(161)
(154)
(149)
(143)
a. The figures in parentheses indicate enemy force requirements if a Korean
division is not withdrawn.
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Allied Maneuver Deployments -- Alternative A
Current Jun 71 Sep 71 Dec 71 Mar 72 Jun 72
MR 1 62,700 59,600 55,100 50,600 46,000 41,500
US 23,500 20,100 15,100 10,100 5,000 0
RVNAF 35,700 36,000 36,500 37,000 37,500 38,000
ROK 3,500 3,500 3,500 3,500 3,500 3,500
MR 2 37,700 37,500
36,800
36
36 000
3
00)
00)
00)
00)
00)
4,300 3,700 2,800 1,900 1,000 0
19,400 20,800 22,800 24,900 26,900 29,000
14,000 13,000 11,500 10,000 8,500 7,000
Cn US
RVNAF
ROK
MR 3
40,500 38,400 32,900 29,700 24,200 21,000
US 4,000 3,400 2,600 1,700 900 0
RVNAF 31,500 30,000 27,800 25,500 23,300 21,000
Thai & Aus 5,000 5,000 2,500 2,500 0 0
MR 4 26,000 25,300 24,200 23,100 22,100 21,000
US -- -- -- -- -- --
RVNAF 26,000 25,300 24,200 23,100 22,100 21,000
a. Figures in parentheses indicate Allied maneuver deployments if a Korean
division is not withdrawn.
b. Figures include 15,000 RVNAF troops assumed to be committed to opera-
tions in Cambodia throughout the period.
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SJ A.Ki 1
from 28,000 to only 22.000 troops The Korean
withdrawal also impacts Significantly in the event
of enemy strategies focused on MR 2 (Cases III and
IV) In both cases the required manpower augmenta-
tion by mid-?1972 is reduced to only 8,000 troops,
More to the point the Korean withdrawal offsets
the advantages gained by ARVN redeployment, In
our previous analysis the substantial redeployment
of ARVN forces meant that the Communists, even in
the face of US withdrawals, would have to increase
the size of their force by some 10,000 combat
troops to mount an offensive strategy in MR 2 by
mid-1972, With a Korean withdrawal the same offen-
sive capabilities could be achieved with 2,000 less
enemy troops,
Alternative B
9 In Alternative B we examiaed a redeployment
scheme that would have the US residual force down
to 64,600 troops including 2 600 combat forces in
MR 2 The effect of this alternative on the force
augmentations required for each strategy is shown
in Table 3,
10, This alternative scheme does not produce
any significant changes in our estimates of enemy
force requirements,, causing them to increase only
on the order of 3,000-4,000 troops as of mid-1972.
Most of this added requirement is felt in MR 2
because of the continued presence of some 2,600
US maneuver troops, thus making Cases III and IV
somewhat more difficult to achieve from the man-
power point of view
11,. Redeployments under Alternative B ha?"e the
apparent advantage of maintaining a greater US
maneuver force presence which is spread more uni-
formly throughout the country during the more
critical months of the 1971-72 dry season. It
should be noted, however that although Alterna--
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Enemy Combat Force Iequire.tents -- Alternative B a/
Thousand Men
Basic
Analysis
Jun 71
Sep 71
Dec 71
Mar 72
Jun 72
Case I
115
(1970 Protracted Warfare)
Case II
(MR 1)
Case III
125
124
124
125
125
126
(MR 2)
(125)
(126)
(128)
(130)
(132)
Case IV
145
139
136
130
128
126
(MR 1 & 2)
(140)
(138)
(133)
(133)
(132)
Case V
135
135
135
135
135
135
(Cambodia)
Case VI
155
150
147
140
138
135
(Mn 1/Cambodia)
Case VII
175
166
158
148
143
140
(GVN/Cambodia)
(167) (160) (151) (148) (146)
a. The figures in parentheses indicate enemy force requirements if a Korean
division is not withdrawn.
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Allied Maneuver Deployments -- Alternative B
Current
Jun 71
Sep 71
Dec 71
Mar 72
Jun 72
M. 1
62,700
57,200
53,600
45,300
43,400
41,500
US
23,500
17,700
13,600
4,800
2,400
0
RVNAF
35,700
36,000
36,500
37,000
37,500
38,000
ROK
3,500
3,500
3,510
3,500
3,500
3,500
MR 2 21
37000
36 400
36,900
37
~500
389000
3
6600
8,
3 ,400)
=39 400)
,
(41.500)
(43,500)
38
r
(45,600)
US
4,300
2,600
2,600
2,600
2,600
2;600
00
RVNAF
19,400
20,800
22,800
24,900
26,900
29,000
ROK
14,000
13,000
11,500
10,000
8,500
7,000
trJ
'
MR 3
40,500
38,300
33,600
31,300
26,600
21,000
US
4,000
3,300
3,300
3,300
3,300
0
RVNAF
31,500
30,000
27,800
25,500
23,300
21,000
Thai
& Aus
5,000
5,000
2,500
2,500
0
0
MR 4
26,000
25,300
24,200.
23,100
21,000
US
--
--
--
--
--
--
RVNAF
26,000
25,300
24,200
23,100
22,100
21,000
a. Figures in parentheses indicate Allied maneuver deployments if a Korean
division is not withdrawn.
b. Figures include 15,000 RVNAF troops assumed to be committed to opera-
tions in Cambodia throughout the period.
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Impact of Withdrawals cn Friendly/Enemy
Force Ratios
12. we pointed out that US with- 25X1
drawals would produce unfavorable changes in the
existing balance between friendly and enemy combat
forces in all regions but MR 2.
13. In Table 5 we show the quarterly changes
in ratios of friendly to enemy forces between now
and mid-1972, assuming that the withdrawals of
friendly forces were made under Alternative A
(the straight line projection). We have arrayed
the data in two ways, the first including maneuver
forces only; the second including RF/PF forces.
The ratios using maneuver forces only are presented
as being more relevant to the type of main force
combat envisioned in the strategies calling for
sustained offensive activities. The ratios in-
cluding RF/PF forces are probably more pertinent
in assessing -.lie balance of forces under conditions
of protracted warfare with its low levels of combat
activity.
14. In either case the balance between friendly
and enemy forces moves generally in favor of the
Communists as Allied forces are withdrawn from
South Vietnam. The situation in MR 2 is particularly
sensitive to the presence of ROK forces. In our
original memorandum the balance between friendly
and enemy forces moved steadily in favor of
friendly forces in MR 2. In the current analysis
the withdrawal of one ROIL division from MR 2 means
that the balance in MR 2 becomes a standoff.
15. The sharp and unfavorable decline in the
balance of forces in MR 3 is due principally to
the assumption that a sizable number of ARVN
troops -- 15,000 -- will continue to be deployed
in Cambodia throughout the period, The unfavorable
balance could be easily reversed as shown in
Table 5, if ARVM forces were returned to MR 3.
In this case, it would not be until near the end
of the first quarter of 1972 that the favorable
balance in MR 3 would begin to fall below the
current favorable balance.
16. Table 5 also shows a particularly unfavor-
able situation in MR 1 where even with the inclusion
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Table 5
Ratio of Friendly to Enemy Forces
Current
Jun 71
Sep 71
Dec 71
Mar 72
Jun 72
Maneuver Forces Only a/
FIR 1
1.8
1.7
1.6
1.4
1.3
1.2
MR 2 b/
1.6
1.6
1.6
1.6
1.6
1.6
(1.7)
(1.7)
(1.8)
(1.8)
(1.9)
MR 3 c:
1.5
1.4
1.1
0.9
0.5
0.4
(2.3)
(1.9)
(1.7)
(1.4)
(1.2)
MR 4
1.7
1.7
1.6
1.5
1.5
1.4
Including RF/PF
MR 1
3.5
3.4
3.3
3.2
3.0
2.9
MR 2 b/
5.5
5.4
5.4
5.4
5.4
5.4
(5.5)
(5.5)
(5.6)
(5.6)
(5.7)
MR 3 c/
6.3
6.1
5.8
5.6
5.3
5.1
(7.0)
(6.7)
(6.5)
(6.2)
(6.0)
MR 4
11.8
11.8
11.7
11.6
11.5
11.5
a. Relates on y friendly maneuver forces to enemy main and oca combat
and combat support forces.
b. Figures in parentheses indicate the ratio if a Korean division is
not withdrawn.
C. Figures in parentheses indicate the ratio if the 15,000 RVNAF troops
are recalled f.!om Cambodia
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of RF/PF forceG the ratios are lowest. This may
become increasingly critical in view of the fact
that the Commui :L,sts have their heaviest concentra-
tion of forces in MR 1, and that is also the ar,:a
where logistic and manpower constraints on offen-
sive options are minimal.
Effect of Withdrawals on Enemy Manpower
Requirements
17. Given a situation in which the Allied pres-
ence is so drastically reduced by mid-1972, i.t
seems likely that enemy casualties will decrease
from their current levels and that the manpower
requirements needed to support each strategy may be
significantly lower than our origin '. estimates.
The extent of the decline in enemy casualties will,
of course, depend on a number of variables, includ-
ing the level and types of air interdiction pro-
grams; the relative effectiveness of US, third-
country, and ARVN forces in inflicting enemy casual-
ties; and, of course, the extent of enemy offensive
activity.
18. If the air interdiction program continues
at an average monthly leve.'. of 10,000 tactical
sorties and 1,000 B-52 sorties, we would not expect
any significant change in enemy casualties attrib-
utable to air interdiction.
19. The influence of other variables such as the
relative effectiveness of US and ARVN forces in
inflicting casualties is more difficult to measure,
but some preliminary judgments are possible. In
Table 6, we show the number of enemy killed in
action (KIA) attributable to US, ARVN, and third
country forces.
20. The table shows clearly that the share of
enemy KIA attributable to US forces has declined
markedly from 61% of the total during the first
quarter of 1969 to 16% during the last quarter of
1970. The South Vietnamese share in the same
periods increased from 33% to 80%. It should be
noted, however, that an unknown share of the KIA
attributable to South Vietnamese forces is due to
US tactical air support.
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Enemy Troops Killed in Action Attributable to Friendly Forces
US ARVN RF/PF Third Country
Per- Per- Per-
Total Number cent Number cent Number cent Number
Per-
cent
Cn
I
1st
Qtr
43,931
26,884
61
10,146
23
4,426
10
2,475
6
2nd
Qtr
49,660
29,778
60
12,330
25
4,353
9
3,199
6
3rd
Qtr
34,013
18,587
55
6,797
20
5,838
17
2,791
8
~-]
4t1
Qtr
32,042
15,489
48
9,395
29
5,804
18
1,354
4
1st
Qtr
27,241
11,399
42
8,290
30
6,084
22
1,468
5
2nd
Qtr
41,435
12,447
30
21,074
51
6,500
16
1,414
3
3rd
Qtr
20,177
5,378
27
8,802
44
5,017
25
910
5
4th
Qtr
18,397
2,983
16
8,547
46
6,197
34
670
4
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21. Table 6 also shows that US and ARVN forces
have rather consistently accounted for about 75% of
enemy KIA, with the share attributable to RF/PF and
third country forces remaining rather constant. As
a measure of the relative efficiency of US and ARVN
maneuver forces, we have examined the KIA figures
in terms of the number of enemy KIA inflicted per
1,000 maneuver troops, as shown below:
Enemy KIA
per 1,000
Maneuver Troops
1969
US ARVN
1st Quarte
r
292 96
2nd Quarte
r
324 117
3rd Quarte
r
219 65
4th Quarte
r
200 89
1st Quarte
r
153 78
2nd Quarte
r
193 197
3rd Quarte
r
93 82
4th Quarte
r
67 76
22. This tabulation shows that as US forces have
withdrawn, ARVN and US forces had by the second
quarter of 1970 approached parity in terms of the
number of enemy KIA per 1,000 maneuver forces.
On the assumption that this parity can be main-
tained and that the enemy maintains his current
posture, it is possible to make highly tentative
estimates of the extent to which enemy casualties
and hence enemy manpower requirements will decline
by June 1972.
L- T....... 10.71 1-..4--.1
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24. A reduction of 30 in enemy manpower require-
ments would loosen the manpower constraints on
Hanoi's choice of offensive strategies. This is
particularly true in terms of reducing strains on
the NVA training capabilities and avoiding, with
the exception of Case VII, drawdowns on manpower
reserves.
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