The Cambodian
Incursion: A Hard Line for Change
by Major Jeremiah S. Boenisch
Introduction
On 1 May 1970, United States and South Vietnamese units launched a ground and
air offensive into neutral Cambodia to eliminate North Vietnamese sanctuaries
used for frequent raids into South Vietnam. Dubbed the Cambodian Incursion by
President Nixon, the U.S. ground operation took place over a 60-day period from
1 May to 29 June and was overlapped by Allied air strikes and a 75 day South
Vietnamese incursion.[1] By combining the efforts of the South Vietnamese,
devastating air power, and army ground forces, the Allied Forces overwhelmed
enemy positions and supply points resulting in thousands of enemy killed and an
unprecedented recovery of enemy materiel. Although the incursion is sometimes
portrayed as a strategic failure, it was not. This paper will illustrate that
the campaign, though unpopular, was actually the key event necessary for
severing the enemy's lines of communications and logistics in Cambodia, aiding
the successful withdrawal program, saving U.S. credibility, and showing the
success of Vietnamization.
Strategic Setting
To set the stage for this operation, it is necessary to understand the relevant
events leading up to the Cambodian Incursion, plus the strategic and political
situation in the Spring of 1970. In 1969, the peace talks between the U.S. and
the North Vietnamese government were stalled in Paris and the Nixon
administration's hopes of reaching a quick end to hostilities had faltered.
Henry Kissinger's secret visits with North Vietnamese leaders to attempt to
establish a negotiated peace had been deadlocked by the intransigence of an
unbending foe. The North Vietnamese were demanding, "America's unconditional
withdrawal coupled with the overthrow of Nguyen Van Thieu's government in
Saigon."[2] This was an untenable position for President Nixon since he
believed that a unilateral withdrawal of American Forces from Vietnam would not
only be destructive and demoralizing to the South Vietnamese, but would damage
U.S. credibility around the world. The President believed, "If, when the chips
are down, the most powerful nation, The United States of America, acts like a
pitiful, helpless giant, the forces of totalitarianism and anarchy will
threaten free nations and free institutions throughout the world."[3] Faced
with the dilemma of how to withdraw U.S. forces while still giving the South
Vietnamese a fighting chance to defend themselves, Nixon chose a broad U.S.
policy designed to bolster the South Vietnamese with substantial American aid
and training called Vietnamization.
The North Vietnamese Army (NVA) and Viet Cong (VC) strategy leading up to the
incursion had been to maintain pressure on the Americans while negotiations
were continuing in Paris. Led by Gen. Vo Nguyen Giap, the northern leaders
wanted and needed success on the battlefield to show that the American goal of
Vietnamization was not going to save South Vietnam. Only three weeks after
Nixon was inaugurated the NVA launched a campaign designed to strike at
American positions throughout South Vietnam. Over the ensuing months NVA forces
would kill an average of 1000 Americans a month.[4]
In direct response, Nixon authorized secret air strikes against NVA outposts in
Cambodia and dropped a half million tons of bombs in a counter NVA campaign
called "Menu."[5] At the same time U.S. and Army of the Republic of Vietnam
(ARVN) troops advanced to the Cambodia border in an effort to push the NVA and
VC out of South Vietnam. Having been pushed back, NVA troops continued to use
the Cambodian border and its neutrality for frequent attacks and as sanctuary
from ground attacks.
During this same time the Cambodian Prime Minister, Lon Nol, ousted longtime
Cambodian leader, Prince Norodom Sihanouk. From the American perspective, the
coup was welcome because Prince Sihanouk had secretly allowed the NVA use of
his country for logistical bases and infiltration routes into South Vietnam
(Reference Appendix B and C).[6] However, an unsympathetic Lon Nol would pursue
both the NVA and the Cambodian insurgents (the Khmer Rouge); touching off a
messy civil war. Without adequate forces to defeat or defend his country Lon
Nol called out to the international community for assistance.[7] Thus, the U.S.
was presented with an opportunity to move into the Cambodian strongholds.
On 20 April 1970, eleven days prior to the Cambodian Incursion, President Nixon
addressed the nation on the situation in Vietnam and announced the withdrawal
of 150,000 American troops. He stated, "We have now reached a point where we
can move…to a longer range program for the replacement of Americans by South
Vietnamese."[8] In what seemed to be a taunting response to Mr. Nixon's speech,
the days leading up to the incursion would be marked by an escalation of NVA
hostilities in Cambodia.
Responding to this apparent provocation, Nixon authorized the Commander of
American forces, General Creighton Abrams, to execute an incursion into
Cambodia. Beyond eliminating the communist sanctuaries, the President's
objectives for the campaign were outlined in his speech on 30 April 1970:
1) Show the success of Vietnamization
2) Buy time for the success of the withdrawal program
3) Uphold U.S. ideals and credibility[9]
General Abrams' operational plan to accomplish these objectives was simple:
destroy the sanctuaries and you remove the ability of the enemy "to raise or
lower the level of combat at will."[10] His method was to use air strikes
followed by South Vietnamese (led by Lt. General Do Cao Tri) and U.S. ground
forces in an attack against sanctuaries and the major port facility,
Sihanoukville (Reference Appendix D for operations into Cambodia). The enemy
forces in the region included the 5th and 7th NVA Divisions as well as the 5th
Viet Cong Division.[11]
Abrams' strike forces would include: U.S. Air Force B-52s, F-4s, RF-4s, O-2s,
etc.; U.S. Army's 1st Cavalry Division, 4th Infantry Division, 25th Infantry
Division, 9th Infantry Division, 11th Armored Cavalry Regiment, 199th Light
Infantry Brigade; South Vietnam's 5th, 9th, 21st, 22d and 23d ARVN infantry
divisions, 1st ARVN Airborne Division and 2d ARVN Armored Brigade.[12]
The Time for Payback
The time for payback had come. North Vietnamese and Viet Cong forces had been
using Cambodia and its neutrality for over five years to capture and kill
American and South Vietnamese troops. The U.S. had respected the neutrality of
Cambodia but had paid a heavy price for doing so. American soldiers lamented
that, "We had lost many men in combat assaults near the Cambodian border while
the gooks would go back into Cambodia, sit there and laugh at us."[13] Coupled
with the payback was the fact that large amounts of supplies and several
divisions of NVA and VC were in the area in preparing for massive strikes
against South Vietnam that would start by taking down Lon Nol and the Cambodian
government (Reference enemy estimates in Appendix D).[14]
An enthusiastic General Abrams would commence the operation to clean out the
sanctuaries on 24 April 1970 with tactical air strikes designed to soften NVA
targets.[15] Five days later, the South Vietnamese ground forces moved into
action, followed by the Americans two days later. The primary operational
objective of the Allied forces was to conduct "search and destroy operations to
find and eliminate NVA and VC sanctuaries in Cambodia and the troops defending
them."[16] The Campaign would span 75 days and have 12 operations of which only
2 would be led by U.S. ground forces (Reference Appendix D for operations).[17]
The Objectives
Cambodia could no longer be used as a safe haven for the NVA and VC. Allied
forces had pushed the enemy out of their strongholds along the border and the
port city of Sihanoukville with relative ease while simultaneously capturing an
incredible amount of materiel (Reference Appendix A for map). More importantly
their tactical and operational efforts achieved most of President Nixon's
strategic objectives for the campaign. To better judge the impact of the
Cambodian Incursion it is helpful to investigate the tactical and operational
effects of the campaign to determine if they met the strategic objectives.
The first objective of the campaign was to show success of the Vietnamization
Program. A major campaign with ARVN forces, taking a major role, presented just
such an opportunity. From the outset the campaign plan would maximize the use
of South Vietnamese forces which according to Nixon, "would be a major boost to
their morale as well as...demonstrate the success of Vietnamization."[18] With
an 8,700 man force, South Vietnamese troops would officially start their
incursion with Operation Toan Tang 42 (Total Victory) on 29 April 1970.[19]
This operation, into the Parrots Beak area, would be a difficult one against
fortified enemy positions (Reference Appendix F for map). U.S. commanders would
watch closely to judge the performance of the South Vietnamese. Some had argued
that they did not fight well and could not survive without American support.
Yet after its first major test, the South Vietnamese forces would engage in
hand to hand combat, out kill, and otherwise outperform the enemy.[20] Before
the Cambodian Incursion was concluded ARVN forces would lead 10 of the
remaining 12 operations. The South Vietnamese Army's performance in the
operation seemed to indicate that the Vietnamization of the war was a success.
As Samuel Lipsman, the author of The Vietnam Experience: Fighting for Time,
stated, "If the Parrots Beak was a test of the feasibility of America's
Vietnamization policy, the ARVN's aggressive mobility and thorough searching
was an encouraging sign."[21]
The second objective, to buy time for the success of the withdrawal program,
was met by using overwhelming force against the sanctuaries. Before going into
Cambodia, American and South Vietnamese forces expected to encounter fierce
resistance. Intel had estimated that at least three divisions of the enemy
awaited the invasion force.[22] However, in most cases the enemy had withdrawn
under fierce bombing and the presence of Allied forces massing along the
border. In fact, one of the primary targets Mr. Nixon mentioned in his 29 April
1970 speech, the Central Office for South Vietnam (COSVN) headquarters, had to
move west of the Mekong River for security (Reference Appendix G for map).[23]
With its radio networks unable to operate, the command and control of enemy
forces broke down causing significant confusion to subordinate enemy
forces.[24]
The Allied air forces, in many cases, were the principal antagonists in
creating this chaos for the enemy. They would fly over 14,000 attack sorties
that obliterated supply caches and enemy positions.[25] U.S. B-52s, based out
of Guam, would fly 653 sorties in 6 of the 12 ground operations.[26] The planes
outfitted for carrying dozens of conventional 750lb bombs, were controlled by
Strategic Air Command, but General Abrams could call up to 60 a day for his
use.[27]
In conjunction with the air forces were four U.S. Army Divisions (1st, 4th,
9th, 25th) who would join in operation Toan Thang 43 and 44 (Total Victory) to
hit areas in Fish Hook (Reference Appendix G for map) and other sanctuaries.
They delivered a knockout punch to enemy forces in the region. As one General
put it, "This Cambodian operation is pure blitzkrieg, like something from World
War II Panzer Division book of tactics."[28]
The combined tactical and operational effect was truly remarkable. In the span
of 75 days the allied missions had resulted in 11, 562 enemy killed and the
capture of an extraordinary amount of materiel (Reference Appendix I).[29] To
put it in perspective, the allied forces captured enough armament to outfit 54
battalions of 450 men each, enough ammunition to sustain the NVA army for a
year, and enough rice to feed the enemy forces for 6 months (Reference
Appendices H and I).[30] Headquarters Military Assistance Command Vietnam
(MACV) estimated, "It would take the enemy a minimum of 9 months to reorganize
his logistics and…up to 6 months to replace the men lost."[31]
It has been speculated that the incursion could have been decisive, if given
the freedom of maneuverability and the time to pursue NVA forces. However, in
response to pressure from the media, the tragic Kent State shootings, and a
public outcry, the President put an operational restriction on the duration and
penetration of the U.S. forces. Although this hampered U.S. forces, the outcome
of the Cambodian Incursion would be seen as one of the most successful
campaigns in the Vietnam War.
By the end of the campaign Allied forces would disrupt a planned NVA offensive,
buy time needed for Vietnamization, and enable the continuation of the
withdrawal of U.S. forces. Within seven months of the Cambodian Incursion over
115,000 troops would come home.[32] For those still stationed along the
Cambodian border things would be quiet for many months to come.
In order to appreciate the third objective of upholding U.S. ideals and
credibility, it is meaningful to look at the Cambodian Incursion in the context
of its influence and outcome. Within three years of the campaign Nixon and
Kissinger extracted the United States from the protracted Vietnam War. They
would be featured for their success as men of the year on the front cover of
Time Magazine. The caption would read "Triumph and Trial" underscoring the long
and difficult struggle to achieve peace in Vietnam.[33] Although not readily
apparent at the time of the Cambodian Incursion, their success began by taking
a hard line with the enemy by backing rhetoric with force. The Incursion was
not an easy choice for the administration, but it represented an opportunity to
reestablish the credibility of the United States and achieve Nixon's goal to
leave Vietnam with honor.
It wasn't an easy road and the fruits of the Cambodian Incursion were not
readily apparent during or shortly after the campaign. The credibility of the
U.S. would take a significant hit and a secret public opinion poll conducted in
Europe and Asia would confirm a drop in American prestige.[34] Many in the
press saw the move into Cambodia as a violation of that nation's neutrality and
an expansion of the war. On college campuses protests and riots would break out
in response to the Incursion and at Kent State University (on 4 May 1970) four
students would be killed and nine wounded by National Guard troops trying to
break up demonstrations.[35]
The events surrounding the Cambodian Incursion looked and felt terrible to many
Americans. It was a miserable time in U.S. history that many want to forget.
However, through the smoke of emotion it is evident that President Nixon had a
clear plan to reestablish the credibility of the United States and he made it
clear to his commanders, his administration, and ultimately the world. In his
speeches on 20 and 29 April 1970, Nixon defended his position upholding the
ideals of the U.S. making it clear that he would not tolerate an enemy that
would "humiliate and defeat us."[36] The enemy would test the President's
resolve by increasing their attacks and Mr. Nixon would make good on his
promise to respond with force.
The path was set and the President was taking responsibility. In his speech on
29 April he put his presidency on the line stating, "Whether I may be a
one-term President is insignificant compared to whether by our failure to act
in this crisis the U.S. proves itself to be unworthy to lead the forces of
freedom in this critical period in world history."[37] As evidenced in his
memoirs and speeches, Nixon believed that the Cambodian Incursion was the best
way to get Americans out of Vietnam while upholding their honor. He had grown
tired of a non-capitulating enemy at the negotiating table and of an enemy who
played a cat and mouse game from a neutral country. His commanders on the
ground supported this notion and believed that the campaign would have a
tremendous effect on the morale of the troops as well as buy the necessary time
to get out. The world would come to understand that this President wasn't
afraid to make the tough decisions.
With those tough decisions Nixon hoped to bring the enemy back to the
negotiating table. The results were difficult to assess after the campaign
because the enemy didn't immediately capitulate. However, two years later the
enemy would concede to American terms at the Paris Peace talks. Henry Kissinger
cited the Cambodian Incursion as a primary contributor to bringing the North
Vietnamese back to the conference table. He believed that "a combination of
factors brought Hanoi to the point of accepting U.S terms…including the attack
on the Cambodian Sanctuaries in 1970."[38]
The conflict between the peace movement and the President's administration
would continue unabated until the end of the war. However, the path to peace
and retaining U.S. credibility started by both destroying the enemies ability
to fight from a neutral country and by a outspoken President who wanted to
leave Vietnam with honor.
Conclusion
In conclusion, the success of the Cambodian campaign was the result of more
than just good tactics. It was a combination of tactical and operational
effects that brought important strategic results. The well executed campaign
would use a devastating combination of air and ground forces to overwhelm the
Viet Cong and the North Vietnamese Army, who had long used the neutrality of
Cambodia as a safe haven. The Allied forces would achieve stunning victories by
killing thousands, crippling logistics and otherwise affecting the enemy's
ability to strike for many months to come. In favor of a hard line approach,
President Nixon used the campaign to take a stand against a non-capitulating
enemy. He had made his promise to the American people to leave Vietnam, but he
would not leave without honor, nor would he make peace at any price. Instead,
the President used the tactical and operational capacity available to him to
establish a hard line with the enemy that would have a positive effect on the
strategic outcome of the campaign. His decision impacted the way the enemy
would view the U.S. and the way the war was fought in the future. The
combination of the President's leadership and the success of the Cambodian
Incursion helped to reestablish U.S. credibility, allowed for a successful
withdrawal program and demonstrated the success of Vietnamization.
Show Footnotes and
Bibliography
Footnotes
[1]. Hillstrom, Kevin., Hillstrom, Laurie C. Vietnam War Almanac (USA: The Gale
Group, 2001), 209
[2]. Kissinger, Henry. Diplomacy (New York: Simon & Schuster, Inc., 1994),
678
[3]. Nixon, Richard. The Cambodia Strike: Defensive Action for Peace, A Report
to the Nation April 30, 1970 (Washington, D.C.:Department of State Publication,
1970), 7
[4]. Diplomacy. 678
[5]. Shawcross, William. Sideshow: Kissinger, Nixon and the Destruction of
Cambodia. (New York: Simon and Schuster, Inc., 1979), 28- 29
[6]. Tho, Tran Dinh. Indochina Monographs: The Cambodian Incursion (Washington
D.C.: U.S. Army Center of Military History, 1979), v
[7]. Hobson, Chris. Vietnam Air Losses: United States Air Force Navy and Marine
Corp Fixed-Wing Aircraft Losses in Southeast Asia 1961-1973 (England: Midland
Publishing, 2001), 203
[8]. Lipsman, Samuel., Doyle, Edward. The Vietnam Experience: Fighting for Time
(Boston: The Boston Publishing Company, 1983), 149
[9]. The Cambodia Strike, 5-7
[10]. The Vietnam Experience: Fighting for Time, 149
[11]. Sigler. David B. Vietnam Battle Chronology U.S. Army and Marine Corps
Combat Operations, 1965-1973 (London: McFarland and Company, Inc., 1992), 116
[12]. Vietnam Battle Chronology U.S. Army and Marine Corps Combat Operations,
1965-1973, 116
[13]. The Vietnam Experience:, Fighting for Time, 164
[14]. The Cambodia Strike: Defensive Action for Peace, 3
[15]. The Vietnam Experience: Fighting for Time, 149
[16]. Vietnam Battle Chronology U.S. Army and Marine Corps Combat Operations,
1965-1973, 116
[17]. Stanton, Shelby L. U.S. Army and Allied Ground Forces in Vietnam: Order
of Battle (U.S., U.S. News and World Report, Inc., 1981), 30
[18]. The Vietnam Experience: Fighting for Time, 149
[19]. The Cambodian Incursion, 53
[20]. Ibid., 56-62
[21]. The Vietnam Experience: Fighting for Time, 178
[22]. Vietnam Battle Chronology U.S. Army and Marine Corps Combat Operations,
1965-1973, 116
[23]. The Cambodian Incursion, 174
[24]. Ibid., 175
[25]. Glasser, Jeffrey D. The Secret Vietnam War: The United States Air Force
in Thailand, 1961-1975 (Jefferson: Mcfarland & Company, Inc., 1995), 148
[26]. Ibid., 17
[27]. Sideshow, 23
[28]. Vietnam Experience: Fighting for Time, 149
[29]. Folkman, D. I., Caine P.D. The Cambodian Campaign 29 April –June 30 1970
(Christianburg: Dalley Book Service, 1970), fig 1 (See Appendix I)
[30]. The Cambodian Incursion, 170-172
[31]. Ibid., 173
[32]. Ibid., 3
[33]. Author unknown, Nixon and Kissinger: Triumph and Trial
(http://www.time.com/time /magazine/article/0,9171,903628,00.html, 1973) Date
accessed: 2 Nov 2006
[34]. Vietnam Experience, Fighting for Time, 184
[35]. Vietnam War Almanac, 208
[36]. The Cambodia Strike, 5-7
[37]. Ibid., 9
[38]. Diplomacy, 692
Bibliography
Boenisch, David M. (personal communication, 5 November 2006). Member was
directly involved in the Cambodian Incursion in the USAF
Folkman, D. I., Caine P.D. The Cambodian Campaign 29 April –June 30 1970
(Christianburg: Dalley Book Service, 1970)
Glasser, Jeffrey D. The Secret Vietnam War: The United States Air Force in
Thailand, 1961-1975 (Jefferson: Mcfarland & Company, Inc., 1995)
Hillstrom, Kevin., Hillstrom, Laurie C. Vietnam War Almanac (USA: The
Gale Group, 2001)
Hobson, Chris. Vietnam Air Losses: United States Air Force Navy and Marine Corp
Fixed-Wing Aircraft Losses in Southeast Asia 1961-1973 (England:
Midland Publishing, 2001)
Kissinger, Henry. Diplomacy (New York: Simon & Schuster, Inc.,
1994)
Lipsman, Samuel., Doyle, Edward. The Vietnam Experience: Fighting for Time
(Boston: The Boston Publishing Company, 1983)
Nixon and Kissinger: Triumph and Trial (http://www.time.com/time
/magazine/article/ 0,9171,903628,00.html, 1973) Date accessed: 2 Nov 2006
Nixon, Richard. The Cambodia Strike: Defensive Action for Peace, A Report to
the Nation April 30, 1970 (Washington, D.C.:Department of State
Publication, 1970)
Nolan, Keith W. Into Cambodia, 1970: Spring Campaign, Summer Offensive
(Presidio Press, 1990)
Rincon, John (personal communication, 2 November 2006). Person has authored
many articles on the Vietnam War. Articles by him can be found at
http://www.militaryhistoryonline.com
Shawcross, William. Sideshow: Kissinger, Nixon and the Destruction of Cambodia.
(New York: Simon and Schuster, Inc., 1979)
Sigler. David B. Vietnam Battle Chronology U.S. Army and Marine Corps Combat
Operations, 1965-1973 (London: McFarland and Company, Inc., 1992)
Tho, Tran Dinh. Indochina Monographs: The Cambodian Incursion (Washington
D.C.: U.S. Army Center of Military History, 1979)
Copyright © 2006 Major Jeremiah S. Boenisch.
Written by Major Jeremiah S. Boenisch. If you have questions or comments on
this article, please contact Jeremiah S. Boenisch at:
jeremiah.boenisch@gmail.com.
About the author:
Jeremiah S. Boenisch is an officer in the US Air Force currently assigned to
the Marine Corp Command and Staff College. He earned his B.S. degree in
Environmental Science and his B.S. degree in Political Science with minors in
Environmental Health and Aeronautical Science from Oregon State University and
his M.A. in Organizational Management from The George Washington University. A
Communications and Information officer with 12 years experience, Major Boenisch
has served within the National Missile Defense Program, The Office of the
Secretary of Defense for Network, Information and Integration, the HQ Air Staff
(A-6) and most recently 2 combat tours in Iraq supporting special operations
forces. Jeremiah is a co-author of Continuity Management, John Wiley
and Sons, 2002.
Published online: 12/16/2006.
* Views expressed by contributors are their own and do not necessarily represent
those of MHO. |
