Foreign Relations of the United States, 1949, The Far East and Australasia, Volume VII, Part 2

740.00119 Control (Korea)/6–2749

Memorandum by the Department of the Army to the Department of State ¹

top secret

Washington , June 27, 1949.

Subject: Implications of a Possible Full Scale Invasion from North Korea Subsequent to Withdrawal of United States Troops from South Korea

1. The attached study was prepared in the Department of the Army by direction of the Secretary of the Army. It was then forwarded to the Joint Chiefs of Staff for appraisal of the strategic and military implications involved. The JCS reviewed the paper without undertaking comment upon the specific conclusions therein but commented on the general military implications posed by the problem itself (Tab C)² and referred the study to the Department of the Army for such further action as the Chief of Staff, U.S. Army, deemed appropriate.

2. In order that this problem may receive continuing study and appraisal by the interdepartmental agencies of the government, it is probable that the study will be forwarded to the Executive Secretary of the National Security Council for use by the Staff in its consideration of United States Policy Toward Asia (NSC 48).³

3. In accordance with your telephone conversation with Lt. Colonel Zierath, P&O, on 24 June, this study is furnished to you informally as a matter of mutual interest.

For the Secretary of the Army:

Walter H. Grant

Lt. Colonel, GSC

[Annex]

The Problem

1. To consider what course of action the U.S. should adopt in the event of full scale invasion from North Korea subsequent to the withdrawal of U.S. troops from Korea.

Facts Bearing on the Problem

2. See Appendix A.

Discussion

3. See Appendix B.

Possible Intermediate Courses of Action

4.a. To encourage the Rhee Government to attempt the peaceful unification of Korea by direct negotiations with the North Korean regime.

b. To begin planning and organizing now in order to bring into being at a later date a Korean underground task force in North Korea.

c. To have U.S. naval forces visit Korean ports from time to time.

Possible Courses of Action

5.a. To implement current emergency evacuation plans to extricate U.S. nationals and military advisory personnel now accredited to the Government of the Republic of Korea.

b. To present the problem to the U.N. Security Council for emergency consideration as a threat to the general peace.

c. To initiate police action with U.N. sanction by the introduction of a military task force into Korea composed of U.S. units and units of other member nations of the United Nations with the objective of restoring law and order and restoration of the 38th parallel boundary inviolability.

d. To reconstitute a U.S. joint task force in South Korea at the special request of the National Assembly of the Government of the Republic of Korea in view of the emergency situation.

e. To extend and apply the Truman Doctrine to Korea.

Conclusions

6.a. That prior to military aggression, the U.S. Government should adopt the possible intermediate courses of action listed in 4a and c, above.

b. That the U.S. should adopt the intermediate course of action 4b only if there is a sincere and responsive effort on the part of the Rhee Government to unify Korea without resort to force and such course of action (4a) is unsuccessful.

c. That if a full-scale military invasion from North Korea becomes a reality, and the Korean Government is unable to successfully counter such move, the U.S. Government should adopt and implement the possible courses of action listed as 5a and b, above.

Recommendations

7. It is recommended that:

a. This study be considered by the Joint Chiefs of Staff in assessing the military implications of the problem.

b. The views of the Joint Chiefs of Staff and a copy of this study be forwarded to the Secretary of Defense for transmittal to the National Security Council for its consideration.

Appendix A

Facts Bearing on the Problem

1. Strength of South Korean Security Forces.

a.	30 May 1949
	Korean Army	71,086
	Korean Coast Guard	5,450
	National Police	50,434
	Total	126,970	(Joint Weeka #74)
b.	Forces which U.S. supplied with arms and equipment:
	Korean Army	65,000
	Korean Coast Guard	4,000
	National Police	35,000
	Total	104,000	(NSC 8/2)

2. Strength of North Korean Security Forces.

a.	30 May 1949
	Peoples Army	46,000
	Police and para-military forces	56,350
	Total	102,350	(ID estimate)
b.	Forces which the USSR support:		(Joint Weeka #71) Unconfirmed

In a pact concluded 17 March, 1949, the Soviet Union agreed to provide necessary arms and equipment for six Infantry Divisions and three Mechanized “Units.” In addition, sufficient arms and equipment to equip eight battalions of “mobile” border constabulary were to be provided. When North Korea has sufficient Air Force trained personnel, the Soviet Union will make available 20 reconnaissance aircraft, 100 fighters, and 30 bombers, light and medium.

3. Divisive and disaffected elements exist within the security forces and the governmental structure of South Korea.

a. Elements of the First and Second Battalions, 8th Regiment, South Korean Army defected 5 May 1949 and entered North Korea.

b. A mine sweeper of the South Korean Coast Guard defected to North Korea on 12 May 1949.

c. South Korean National Assembly voted down (7 Feb 49) resolution for immediate withdrawal of U.S. troops by vote of 96 to 39. Resolution was brought to vote by petition bearing 71 signatures.

d. South Korean National Assembly on 2 June 49, by a vote of 82–61, asked President Rhee and his Cabinet to resign. The resolution was a motion of censure over internal policies of the officials of the Rhee government.

4. Report of the U.S. delegation on the Joint USSR–US Commission on 20 August 1947 indicated that Soviet aims in Korea are to bring the entire country under Soviet control.⁴

5. The U.S. will complete withdrawal of its occupation forces from Korea on 30 June 1949 (NSC 8/2).

6. On 27 December 1948 the USSR reported complete withdrawal of its occupation forces from Korea on 25 December 48 (Associated Press). There is evidence that the Soviets left 2000 military advisory personnel and 1000 security personnel in North Korea.

7. The United Nations Commission on Korea, on 23 May 1949, in referring to troop withdrawal, passed a resolution which in part states:

“Resolves that while problem remains to be a problem of the United Nations it is the opinion of this commission that under the General Assembly resolution of 12 December 1948, this commission assumes no responsibility regarding either the timing nor the facilitating of the withdrawal of forces of Occupying Powers”.

8. The UN resolution on Korea of 12 December 1948 provided among other things for the establishment of a UN commission in Korea to facilitate the removal of barriers to economic, social and other friendly intercourse caused by the division of Korea; to observe and consult in the further development of representative government based on the freely expressed will of the peoples; to observe the actual withdrawal of the occupying forces and verify the fact of withdrawal when such has occurred; and for this purpose, if it so desires, request the assistance of military experts of the two occupying powers. The resolution further called upon member states, the government of the Republic of Korea, and all Koreans to afford every sustenance and facility to the commission in the fulfillment of its responsibilities; called upon member states to refrain from any acts derogatory to the results achieved and to be achieved by the UN in bringing about the complete independence and unity of Korea; and recommended, that member states in establishing relations with the government of Korea, take into consideration that the government of the Republic of Korea has been established as a lawful government and that this is the only such government in Korea.

9. Through the Cairo Declaration of 1 December 1943 the United States, United Kingdom, and China agreed that “in due course Korea shall become free and independent.” The USSR became party to this commitment by adhering to the Potsdam Declaration when it declared war on Japan on August 8, 1945.⁵

Appendix B

Discussion

possible intermediate courses of action

a. To encourage the Rhee Government to attempt the peaceful unification of Korea by direct negotiations with the North Korean regime.

Advantages:

1. Might forestall military aggression by North Korea.

2. Such action is responsive to the universal aspiration of the Korean people for national unity.

3. The unification attempt by the South Korean government would be a psychological weapon placing national interests, independence and sovereignty above alleged big power politics, and would lend credence to their true nationalist aspirations.

4. Would represent an effort to settle differences by pacific means.

5. Failure of North Korea to cooperate would further illustrate North Korean intransigence and subservience to the USSR.

Disadvantages:

1. Might be subject to interpretation as a sign of weakness and thus might inculcate North and South Korean belief in the insecurity of the Republic of Korea.

2. Incorporation with elements of North Korea on a coalition basis would introduce Communist elements into the Korean government, and might lead eventually to its subversion by political means.

Comment:

The North Korean regime would find it hard to reject a genuine effort to achieve unification on an exclusively Korean basis without U.S. or Soviet interference. At least it would be deprived of an effective propaganda issue. If unification were actually achieved, the dislocations resulting from arbitrary division of the country at the 38th parallel would be eliminated and the development of a viable Korean economy and polity would be made possible. In any truly representative system the non-Communist majority should be able to maintain the independent and democratic character of Korea. It is improbable, however, that the North Korean regime, controlled from Moscow, would accept unification except in terms of a coalition government rigged to facilitate Communist infiltration and eventual domination of the entire country. It is equally improbable that Rhee, relying on UN recognition and U.S. support, would consent to compromise his position by initiating such negotiations with the North Korean regime. Rhee would probably denounce such a suggestion violently and publicly, with bitter reference to similar U.S. efforts in China in 1946, and the ultimate fate of the Chinese National Government.

b. To begin planning and organizing now in order to bring into being at a later date a Korean underground task force in North Korea.

Advantages:

1. The North Korean regime is unrepresentative and therefore vulnerable.

2. Would permit the initiative in the formation of a counter-revolutionary effort.

3. Might eventually so weaken the control of the North Korean government as to facilitate unification of Korea.

Disadvantages:

1. Unless carefully planned and controlled, such an undertaking might be exposed and lead to harsh reprisals which would redound to the disadvantage of the Korean masses.

2. Would justify Communist subversive action in South Korea.

3. Might serve as a stimulus to North Korean overt action against South Korea and an excuse for such action.

Comments:

The organization of an underground in North Korea might by subversive activity prevent North Korean aggression against South Korea, and, in the event of such aggression, might seriously impair the effectiveness of North Korean forces. It would be a gamble with, the possibility of far-reaching successes. Properly supported and covertly guided by U.S. agencies, it could likewise become an excellent intelligence barometer of USSR intentions. It should be implemented under indigenous South Korean impetus only if course a, above, is tested, tried and unsuccessful.

c. To have U.S. naval forces visit Korean ports from time to time.

Advantages:

1. Demonstrate to Korean Government continued U.S. interest in the country.

2. Tend to deter overt aggression by the North Korean government.

Disadvantages:

1. Might inadvertently involve U.S. naval ships in a civil war.

Comments:

Ambassador Muccio has recommended the visit of U.S. naval forces to Korea shortly after the completion of the withdrawal of U.S. Army troops. The Chief of Naval Operations is considering a request to COMNAVFE for his recommendations as to the composition of the naval force and the suggested date for this visit.⁶

possible courses of action

Apparently South Korean security forces are sufficiently organized, trained, and equipped to meet external aggression precipitated by North Korean armed forces as now constituted. Full scale invasion of South Korea by the North Koreans would indicate an all-out effort to acquire control and domination of the Korean peninsula. The Peoples’ Army of North Korea hardly retains the capability of sustained and comprehensive military operations without Chinese Communist and Soviet-Manchurian aid and support. If the U.S. does not adopt a course of action to counter full scale invasion by Communist forces, the Republic of Korea might be overthrown and the Korean peninsula lost to Communist domination by default. U.S. rehabilitation efforts and sponsorship of an independent Korea would then have been a fruitless undertaking. International recrimination would be far reaching to the effect that the U.S. had not fulfilled its public pronouncements to continue support to the Republic of Korea. Some course of action, therefore, would appear mandatory.

The advent of large scale uprisings, coup d’etat and mass disorder throughout Korea subsequent to U.S. troop withdrawal should not be a matter for direct U.S. intervention and should be strictly one of internal dislocation which must be handled by the Korean authorities themselves. The South Korean security forces as now constituted possess the capability of coping with problems of internal order unless large scale defections materialize.

With the above as a basis, specific possible courses of action in the event of an invasion of South Korea after U.S. withdrawal are discussed below.

a. To implement current emergency evacuation plans to extricate U.S. nationals and military advisory personnel now accredited to the Government of the Republic of Korea.

Advantages:

(1) Removes U.S. nationals from the scene of internal revolt, and relieves U.S. responsibility for their security.

(2) Minimizes U.S. involvement in a dangerous situation with unknown complexities.

Disadvantages:

(1) Implies U.S. acknowledgement of the inability of the Korean Government to provide security for foreign nationals with a consequent lessening of confidence in the ability of the Korean security forces by the South Koreans.

(2) May serve as a propaganda weapon for convincing the Korean people that the U.S. has no intention of fulfilling its promises of continued support.

Comment:

Prudence dictates that this course of action must be invoked if the situation becomes alarmingly dangerous. The U.S. action can be characterized as a temporary expedient until the restoration of law and order. This course of action is consonant with Far East Command’s directives and emergency plans.

b. To present the problem to the U.N. Security Council for emergency consideration as a threat to the general peace.

Advantages:

(1) Indicates U.S. recognition of the problem as one of an international character since the U.N. has been largely instrumental in creating and approving this new government.

(2) Allows for a proper reference to the Security Council and operation of the instrumentalities which were created for such purposes.

(3) Forces the Soviets to declare themselves, and is a test of their cooperative or non-cooperative intentions.

(4) Removes the onus of U.S. unilateral responsibility and action.

Disadvantages:

(1) May require the U.N. to act without the properly organized machinery to enforce its dictums, thus weakening its arbitration capabilities.

(2) May involve delays, debate, and recriminations while the situation in the meantime continues to deteriorate.

Comment:

Although the Government of the Republic of Korea is not a member of the U.N., it is established under U.N. auspices and recognized by the U.N. It can bring its case before the Security Council under the terms of the charter. It may be necessary for the U.S. to sponsor such a move if the situation becomes intolerable. This course of action appears logical and necessary, whatever else is done. A Soviet veto will block any Security Council effectiveness in dealing with the problem expeditiously. A Soviet abstention, although a non-committal approach, will permit police action measures and sanctions if such appear warranted later.

c. To initiate police action with U.N. sanction by the introduction of a military task force into Korea composed of U.S. units and units of other member nations of the United Nations with the objective of restoring law and order and restoration of the 38th parallel boundary inviolability.

Advantages:

(1) In the the absence of an international police force, U.N. ability to proceed with a militant enactment of its directives and resolutions will enhance its prestige and increase its peace enforcement potentialities.

(2) Might lead to an effective and early restoration of the status quo ante in contrast to interminable aspects of other disputes, e.g., Greece, Israel, Kashmir, Indonesia.

(3) Might provide a recognized lever, the employment of which could have a salutary effect on future violations of law and order or disregard for U.N. resolutions.

Disadvantages:

(1) May require Congressional authority for U.S. forces to participate with consequent delays readily apparent.

(2) Involves a militarily disproportionate expenditure of U.S. manpower, resources, and effort at a time when international relations in Europe are in precarious balance.

Comment:

This course of action is unsound militarily and should be considered only in the light of developments of course of action b above if it becomes apparent that all other methods have failed. The U.S. position should be firm and unequivocal and call for complete cooperation and full participation by other member nations.

d. To reconstitute a U.S. joint task force in South Korea at the special request of the National Assembly of the government of the Republic of Korea in view of the emergency situation.

Advantages:

(1) Resolute action will command universal respect.

(2) The anti-Communist movements world wide would be inspired and strengthened by U.S. support of a threatened, legally-constituted regime.

(3) The proximity of occupation troops in Japan for reinforcing purposes lends an aura of power and decisiveness to this action which might have sufficient deterrent effect to cause North Korean withdrawal to the 38th Parallel and obviate police action engagement.

Disadvantages:

(1) Commits the U.S. to a unilateral course of action and responsibility in Korea from which it so recently has struggled to extricate itself.

(2) The commitment of manpower and resources to this endeavor cannot be spared; it is a retrogressive step with unavoidable financial and logistical complications omnipresent.

(3) It would open the U.S. to criticism for recently having withdrawn its military forces over the objections of certain governments (Korea, China, Philippines).

(4) The Chinese Communists might seize the opportunity to align themselves openly with the North Korean elements against the U.S.

(5) South Korean forces might note the willingness of U.S. intervention and resort to dilatory tactics, placing the brunt of military activity on the U.S. to its extreme embarrassment.

(6) It might justify re-entry of Soviet troops into North Korea.

(7) It might lead to a long and costly involvement of U.S. forces in an undeclared war.

Comment:

Although the U.S. might consider this action necessary on the basis of political considerations, a reconstitution of military forces in Korea would have serious military implications and is unsound from a military point of view. It would lead further to charges of temporization and imperialist tendencies. Unilateral U.S. military action would not finalize the situation and might lead to world conflict.

e. To extend and apply the Truman Doctrine to Korea.^*

Advantages:

(1) Would represent a tangible indication of interest in and support to a part of the world rapidly succumbing to Communism.

(2) In a geographical sense would act as a deterrent to the Communist advance toward Japan.

Disadvantages:

(1) Would necessitate the conversion of projected ECA funds for Korea from an indirect economic and rehabilitation program to direct supply of additional large military expendables and armament.

(2) Lead to misconception of all out U.S. efforts to perpetuate a government which may not continue to be completely supported by the popular will.

(3) Add to the strain on the U.S. Government now faced with the possibility of deficit spending.

(4) Might subtract from the military assistance programs for other nations of a higher priority consideration and would consequently be militarily undesirable and strategically unsound.

Comment:

An analogy to the situation in Greece whereby legally-constituted governments are threatened by militant Communism and tyranny can he drawn. Thereafter any similarity disappears. Greece was a World War II battleground in which the Western Powers were about to lose the capitalizing effect of restoration and rehabilitation efforts as well as an area considered strategically vital. Korea is a liberated area which did not contribute to the victory and is in the opinion of the Joint Chiefs of Staff of little strategic value (JCS 1483/44).⁷ To apply the Truman Doctrine to Korea would require prodigious effort and vast expenditures far out of proportion to the benefits to be expected.

Enclosure

[June 23, 1949]

Memorandum for the Chief of Staff, U.S. Army ⁸

1. The Joint Chiefs of Staff understand that the Chief of Staff, U.S. Army will take such further action on the study “Implications of a Possible Full-Scale Invasion from North Korea Subsequent to Withdrawal of U.S. Troops from Korea” as he may deem appropriate.

2. The Joint Chiefs of Staff have considered the military implications of the study and submit the following comments:

a. From the strategic viewpoint, the position of the Joint Chiefs of Staff regarding Korea, summarized briefly, is that Korea is of little strategic value to the United States and that any commitment to United States use of military force in Korea would be ill-advised and impracticable in view of the potentialities of the over-all world situation and of our heavy international obligations as compared with our current military strength.

b. The conclusions of the study are consistent with the foregoing.

c. The Joint Chiefs of Staff desire to emphasize that, as concluded in the study, the possible courses of action listed as 5c and 5d would be militarily unsound. The first of these, which envisages the introduction of a military task force into Korea composed of United States units and units of other member nations of the United Nations, would be practicable only if and when it has become possible to organize United Nations armed forces for the Security Council under the terms of Article 43 of the United Nations Charter. The second of these possible courses of action would amount to reoccupation of South Korea. This, for reasons well stated in the study, would invite serious consequences while offering no tangible advantage. Furthermore, either course of action might lead to major military involvement.

1. The memorandum was directed to the attention of Mr. Niles W. Bond, Assistant Chief of the Division of Northeast Asian Affairs.
2. See enclosure, p. 1056.
3. See the memorandum to the National Security Council, dated December 30, p. 1215.
4. See telegram 288 from Seoul, August 20, 1947, Foreign Relations, 1947, vol. vi, p. 757.
5. See Foreign Relations, The Conferences at Cairo and Tehran, 1943, pp. 448–449; ibid., The Conference of Berlin (Potsdam), vol. ii, pp. 1474–1476.
6. See telegram 1862, November 4, from Seoul, p. 1093.
7. (The principle now applied to Greece and Turkey of: assisting those peoples and governments who of their own volition actively oppose Communist encroachment and are threatened by tyranny; the containment of Communism).
7. See NSC 8/2, March 22, p. 969.
8. Designated “Tab C” in the source text; dated June 23, 1949.