Timeline of the Vietnam War (1963)

The defeat of the South Vietnamese Army (ARVN) in a battle in January set off a furious debate in the United States on the progress being made in the war against the Viet Cong in South Vietnam. Assessments of the war flowing into the higher levels of the U.S. government in Washington were wildly inconsistent, some citing an early victory over the Viet Cong, others a rapidly deteriorating military situation. Some senior U.S. military officers and White House officials were optimistic; civilians of the Department of State and the CIA, junior military officers, and the media were decidedly less so. Near the end of the year, U.S. leaders became more pessimistic about progress in the war.

Although the U.S. denied that it had combat soldiers in South Vietnam, U.S. soldiers routinely participated in combat operations against the Viet Cong. The number of U.S. soldiers in South Vietnam rose to more than 16,000 by year's end with 122 combat deaths.

The President of South Vietnam Ngo Dinh Diem initiated a brutal crack-down on protests by Buddhists against his (largely Roman Catholic) government that caused consternation in the U.S and concern that the Diem government was failing. In November, Diem was overthrown and killed in a coup d'etat by his military, with the tacit acquiescence of the United States. A military junta headed by General Duong Van Minh replaced Diem. United States President John F. Kennedy was assassinated three weeks later. Lyndon Johnson became President of the United States. Johnson did not make any major changes in Kennedy's policies or team of policy advisers on Vietnam.

Most of the statements and reports quoted below were secret and not shared with the American public.

January
The Battle of Ap Bac was the first major combat victory by the Viet Cong against regular South Vietnamese and American forces. The battle took place near the hamlet of Ap Bac, 65 km southwest of Saigon in the Mekong Delta. Forces of the 7th Division of the Army of the Republic of Vietnam (ARVN), equipped with armored personnel carriers (APCs) and artillery and supported by American helicopters, confronted entrenched elements of the Viet Cong 261st and 514th battalions. The heavily outnumbered Viet Cong inflicted about 200 casualties on the Vietnamese army, killed 3 American advisers, and shot down five helicopters. The Viet Cong, after several defeats in the Delta, had devised tactics to combat American helicopters and armored vehicles.
 * January 2

U.S. Military Assistance Command, Vietnam (MACV) Commander General Paul D. Harkins declared the battle a victory for ARVN because the Viet Cong had abandoned the battlefield. American adviser Lt. Col. John Paul Vann who observed and directed the battle from a small airplane, called it a "miserable damn performance" by ARVN because the Viet Cong escaped after inflicting heavy casualties on the South Vietnamese.

State Department officer Roger Hilsman, who had counterinsurgency experience in World War II, said after a visit to Vietnam that "things are going much better than they were a year ago" but "not nearly so well as [General] Harkins and others might suggest."
 * 2 January

Hilsman also talked to General Edward Rowny who had accompanied the ARVN on 20 combat operations. Rowny criticized the ARVN for delaying operations while waiting for air strikes and for its indiscriminate shooting of civilians in bombed-out villages. He was also critical of the lack of U.S. Air Force support for helicopter operations and the micro-management of the war by CINCPAC. He noted that many competent U.S. captains and majors "are becoming strong advocates of fewer sweep operations and more civil and political action programs."

In his State of the Union address to Congress President Kennedy said "the spearpoint of aggression has been blunted in South Vietnam."
 * 14 January

General Harkins presented his Comprehensive Plan for the Vietnam War. He envisioned an increase in South Vietnamese forces (ARVN plus Civil Guard and Self Defense Forces) to 458,500 personnel by mid-1964 and thereafter to decrease, the war presumably winding down. Harkins foresaw that U.S. military personnel in South Vietnam would be reduced to 12,200 by mid 1965 and to 1,500 in mid 1968. MACV would be abolished by 1 July 1966.
 * 19 January

Army Chief of Staff General Earle Wheeler returned to Washington after heading a delegation of senior U.S. military officers to South Vietnam. Wheeler's report was highly optimistic. "The situation in South Vietnam has been reoriented, in the space of a year and a half, from a circumstance of near desperation to a condition where victory is now a hopeful prospect." Wheeler commented that press reports about the Battle of Ap Bac had caused "great harm...Public and Congressional opinion in the United States has been influenced toward thinking that the war effort in Vietnam is misguided, lacking in drive, and flouts the counsel of United States advisers. Doubts have been raised as to the courage, the training, the determination and dedication of the Vietnamese armed forces."
 * 30 January

February
U.S. army adviser Col. Daniel B. Porter reported to General Harkins from the field that "In many operations against areas of hamlets which are considered to be hard-core VC [Viet Cong] strongholds, all possibility of surprise is lost by prolonged air strikes and artillery bombardments prior to the landing or movement of troops into the area The innocent women, children and old people bear the brunt of such bombardments."
 * 13 February

March
In an issue of Army Magazine devoted to guerrilla warfare a letter to the editor explained the U.S. army's lack of attention to counterinsurgency. "The whole field of guerrilla operations was the burial place for the future of any officer who was sincerely interested in the development and application of guerrilla war. The conventionally trained officer appears to feel that guerrilla operations are beneath his dignity...
 * 8 March

Colonel Wilbur Wilson reported that the promising Buon Enao (Civilian Irregular Defense Group) project was in danger. The South Vietnamese government was confiscating weapons from the Montagnard self-defense forces created and armed by the CIA in Buon Enao. He said that "the effectiveness of the Buon Enao concept will decrease sharply throughout all the highlands" and "VC [Viet Cong] incidents will increase rapidly once the VC learn that...food, manpower, and freedom of movement can be obtained without combat."
 * 12 March

MACV did not respond positively to the concern and continued shifting Special Forces soldiers away from pacification projects, also called hearts and minds programs, such as Buon Enao into purely military operations against the Viet Cong. By the end of 1963, Darlac province where Buon Enao was located had "one of the highest rates of Communist activity in the country."

General Harkins and MACV issued a report stating that "barring greatly increased resupply and reinforcement of the Viet Cong by infiltration, the military phase of the war can be virtually won in 1963." This optimistic statement conflicted with negative assessments coming in from a large number of military advisers in the field
 * 20 March

Prime Minister Pham Van Dong of North Vietnam told a Polish diplomat that a Geneva Conference should be convened to establish a neutral coalition government in South Vietnam. Pham said that the U.S. could thus "withdraw with honor satisfied" and that the unification of North and South Vietnam would be accomplished only gradually.
 * 27 March

April
Lt. Col. John Paul Vann departed Vietnam for an assignment in the United States. Vann met with and briefed many officers at the Pentagon about the military situation in Vietnam. He was invited to brief the Joint Chiefs of Staff (JCS) on July 8. However, his briefing was cancelled at the last minute, apparently by the Chairman of the Joint Chiefs of Staff General Maxwell Taylor. Vann's proposed briefing to the JCS was at odds with what General Harkins was telling Washington. He planned to say that the body counts ARVN reported of Viet Cong killed were inflated and included many non-combatants and that the indiscriminate use of artillery and air strikes was alienating the Vietnamese population.
 * 3 April

A National Intelligence Estimate by the intelligence community of the U.S. stated: "We believe that Communist progress has been blunted...The Viet Cong can be contained militarily and...further progress can be made in expanding the area of government control and in creating greater security in the countryside."
 * 17 April

CIA Director John A. McCone had rejected an earlier draft which had been far less optimistic. He directed the analysts to seek out the views of senior U.S. military and civilian policymakers, most of whom were far more optimistic. The earlier draft had read: "The struggle in South Vietnam will be protracted and costly [because] very great weaknesses remain and will be difficult to surmount." The weaknesses of the South Vietnamese government were "lack of aggressive and firm leadership at all levels of command, poor morale among the troops, lack of trust between peasant and soldier, poor tactical use of available forces, a very inadequate intelligence system, and obvious Communist penetration of the South Vietnamese military organization.

The shift in the emphasis of the report from pessimistic to optimistic has been cited by CIA studies as an example of distorting intelligence to suit the political wishes of senior government officials.

May
A U.S. Army (Pacific) intelligence bulletin was titled "Enemy Presses Hard on Shaky South Vietnam Regime." The report said that Viet Cong attacks during the month of March had reached an all time high of 1,861 and that the attacks were larger in scale and dispersed over a larger area than previously.
 * 1 May

Government troops opened fire on Buddhist protesters in the city of Hue. The Buddhists were gathered to protest a government ban of flags to celebrate the Buddha's birthday. South Vietnam was 70 percent Buddhist although President Diem, his family, and most of his close political allies were Roman Catholic.
 * 8 May

Returning to the U.S. after a briefing from General Harkins on the military situation in South Vietnam, McNamara was quoted by The New York Times as saying he was "tremendously encouraged" by the military progress made in South Vietnam. The newspaper article was titled "McNamara Says Aid to Saigon Is at Peak and Will Level Off."
 * 12 May

Illustrating the strains in the relationship between President Diem and the U.S. government, Diem was reported in the Washington Post as saying that "South Vietnam would like to see half of the 12,000 to 13,000 American military stationed here leave the country."
 * 12 May

The U.S. Army issued guidance to its personnel in South Vietnam for dealing with the media. "Your approach to the questions of the press should emphasize the positive aspects of your activities and avoid gratuitous criticism. Emphasize the feeling of achievement, the hopes for the future, and instances of outstanding individual or personal credibility by gilding the lily.  As songwriter Johnny Mercer put it, "You've got to accentuate the positive and eliminate the negative."
 * 16 May

June
The Hue chemical attacks occurred when soldiers of the Army of the Republic of Vietnam (ARVN) poured liquid chemicals from tear gas grenades onto the heads of praying Buddhists in Huế. The Buddhists were protesting against religious discrimination by the regime of President Diem. Sixty-seven people were hospitalized for blistering of the skin and respiratory ailments.
 * June 3

A Vietnamese Mahayana Buddhist monk, Hòa thượng Thích Quảng Đức, burned himself to death at a busy street intersection in Saigon. He was protesting the persecution of Buddhists by Diem's government. Associated Press photographer Malcolm Browne took a photograph of the incident which was published on the front page of nearly every newspaper in the world.
 * June 11

July
At a press conference, President Kennedy said of South Vietnam. "We are not going to withdraw...for us to withdraw would mean a collapse not only of South Vietnam, but of Southeast Asia. So we are going to stay there."
 * 17 July

At a conference of U.S. military leaders in Hawaii, Secretary McNamara called for a withdrawal of 1,000 American military personnel from South Vietnam by the end of 1963, a more rapid withdrawal than had been proposed by General Harkins on January 19.
 * 23 July

August
Henry Cabot Lodge, Jr, a Republican from a prominent political family, was sworn in as the new U.S. Ambassador to Vietnam, replacing Frederick Nolting.
 * 12 August

In a letter to The New York Times, Madame Nhu, sister-in-law of President Diem, defended her strong criticisms of protesting Buddhist monks. She wrote, "I would clap hands at seeing another monk barbecue show, for one can not be responsible for the madness of others."
 * 14 August

President Diem declared martial law. His brother Ngo Dinh Nhu sent troops loyal to him to raid Buddhist pagodas all over the country. More than 1,000 Buddhists and others were arrested.
 * 21 August

The State Department sent Cable 243 to Ambassador Lodge in Saigon stating: "US Government cannot tolerate situation in which power lies in Nhu's hands. Diem must be given chance to rid himself of Nhu and his coterie and replace them with best military and political personalities available. If, in spite of all of your efforts, Diem remains obdurate and refuses, then we must face the possibility that Diem himself cannot be preserved...You may also tell appropriate military commanders we will give them direct support in any interim period of breakdown central government mechanism." The cable was controversial within the Kennedy Administration as not all the major policy makers had been consulted before it was dispatched. Historian John W. Newman described it as "the single most controversial cable of the Vietnam War."
 * 24 August

After an acrimonious debate at the White House concerning U.S. support for a coup d'état to overthrow Diem, President Kennedy said to participants, "My government is falling apart."
 * 28 August

The President of France Charles de Gaulle made a public statement implying that North and South Vietnam should be united and "independent of outside influences." The Kennedy Administration was immediately concerned about the impact of the De Gaulle pronouncement and acted to reduce its impact. Kennedy would say on September 2 that De Gaulle was not being helpful and that De Gaulle said, in effect, "why don't we all just go home and leave the world to those who are our enemies."
 * 29 August

The CIA reported to Washington that "this particular coup is finished." General Harkins said the Vietnamese generals "were not ready" to stage a coup. At a White House meeting, Vice President Lyndon Johnson said he had never been sympathetic with the proposal to change the government in Vietnam by plotting with Vietnamese generals. Now that the generals had failed to organize a coup, he thought we ought to reestablish ties to the Diem government as quickly as possible and get forward with the war against the Viet Cong. "We must," he said, "stop playing cops and robbers."
 * 31 August

September
President Kennedy had a televised interview with journalist Walter Cronkite. The President said that, while the U.S. could help, it was the Vietnamese who had to win the war. He added, "I don't agree with those who say we should withdraw. That would be a great mistake."
 * 2 September

The Battle of Go Cong was a small battle during the Vietnam War after the General Staff of the National Liberation Front called for "another Ap Bac" on South Vietnamese forces.
 * 3 September

General Taylor, the Chairman of the Joint Chiefs of Staff, approved a plan (OPLAN 34A) for covert military raids in North Vietnam.
 * 9 September

Marine Corps General Victor Krulak and Department of State official Joseph Mendenhall briefed President Kennedy on their recent visit to South Vietnam. Krulak said that the war could be won "if the current U.S. military and sociological programs are pursued." Mendenhall said the South Vietnamese government had broken down by the "pervasive atmosphere and fear and hate arising from the police reign of terror." Kennedy commented, "You two did visit the same country, didn't you?"
 * 10 September

At the same meeting Rufus Phillips, head of the USAID mission in Vietnam, said that the war in the Mekong Delta was going poorly. The strategic hamlets in the Delta were being chewed to pieces by the Viet Cong. Krulak disagreed, saying that only 0.2 percent of strategic hamlets had been overrun by the Viet Cong. John Mecklin, of the U.S. Embassy in Saigon said that "conditions in Vietnam have deteriorated so badly that the U.S. would be drawing to a three card straight [i.e. accepting an unlikely probability] to gamble its interests there on anything short of an ultimate willingness to use U.S. combat troops."

Ambassador Lodge cabled Washington his estimate of the current situation in Vietnam: "It is worsening rapidly...the time has arrived for the US to use what effective sanctions it has to bring about the fall of the existing government and the installation of another" and "study should be given [to] the suspension of aid." A meeting later that day between President Kennedy and his advisers was indecisive."
 * 11 September

At a press conference, President Kennedy said the U.S. opinion of the Vietnam War was, "What helps to win the war, we support; what interferes with the war effort, we oppose....We are not there to see a war lost.
 * 12 September

British counterinsurgency expert Robert Grainger Ker Thompson told Ambassador Lodge that Hanoi was willing to make major concessions to ensure an American withdrawal from South Vietnam. Other diplomats with high-level contacts in Hanoi believed the same.
 * 12 September

Ambassador Lodge cabled Washington recommending study be given to the U.S. response if Ngo Dinh Nhu, in the course of negotiating with North Vietnam, should ask the U.S. to leave South Vietnam or to make a major reduction in forces.
 * 13 September

Polish diplomat Mieczyslaw Maneli reported to Warsaw and the Soviet Union that "Saigon is buzzing with rumors about secret contacts between Diem-Nhu and Ho Chi Minh." Many diplomats in Hanoi and Saigon believed that Nhu, the President's brother, was seeking an accommodation with North Vietnam because he had concluded that the U.S. was going to remove him from power.
 * 18 September

October
Secretary of Defense McNamara and Chairman of the Joint Chiefs of Staff General Maxwell Taylor returned from a fact-finding trip to South Vietnam and submitted their report to President Kennedy in a meeting at the White House. McNamara and Taylor concluded that "the military campaign has made great progress and continues to progress" and that "there is no solid evidence of the possibility of a successful coup." A White House statement said that "Secretary McNamara and General Taylor reported their judgment that the major part of the U.S. military task can be completed by the end of 1965, although there may be a continuing requirement for a limited number of U.S. training personnel. They reported that by the end of this year, the U.S. program for training Vietnamese should have progressed to the point where 1,000 U.S. military personnel assigned to South Viet-Nam can be withdrawn."
 * 2 October

American troops in South Vietnam at this time numbered 16,732.

Cable 534 was sent to Ambassador Lodge in South Vietnam from the Department of State with instructions for Lodge to press President Diem on a number of issues. Pending favorable action of the part of Diem, some economic aid programs would be suspended which, in the view of the State Department, would not have an adverse impact on the war against the Viet Cong for two to four months. Among other things, Diem was to be enjoined to cease criticism of the United States and to focus on a serious military situation in the Mekong Delta. His strategy should be to hold territory and protect rural rather than having the ARVN undertake military sweeps of only temporary value.
 * 5 October

In National Security Action Memorandum 263 (NSAM 263) John F Kennedy ordered the withdrawal of 1,000 American troops from South Vietnam without any public announcement of the withdrawal. Kennedy's decision to withdraw 1,000 soldiers from Vietnam is sometimes cited as part of a possible motive to assassinate him. (This theory is presented in Oliver Stone's film JFK.)
 * 11 October

The New York Times echoed several other publications by urging that the Kennedy Administration not reject the idea of a neutral South Vietnam.
 * 19 October

The Army Attache Colonel Jones of the American Embassy in Saigon met with Colonel Nguyen Kuong of ARVN. Kuong said that "A small, powerful group of military officers who can control sufficient forces are prepared to launch a coup against the Diem government. He outlined how they can assassinate Diem almost at will, replace corrupt/incompetent military, cabinet, and province officials, prosecute the war against the VC, recall political refugees from France/USA, and establish a new government. While this group fears Diem, they especially fear Mr. [Ngo Dinh] Nhu who they consider will surely succeed Diem and who will seek reunification of North and South Vietnam through neutralist solution.
 * 22 October

The State Department in Washington issued a secret report titled "Statistics on the War Effort in South Vietnam Show Unfavorable Trends." The report said that "since July 1963, the trend in Viet Cong casualties, weapons losses, and defections has been downward while the number of Viet Cong armed attacks and other incidents has been upward. A series of telegrams from Ambassador Lodge to President Kennedy was equally pessimistic, stating, that we are "doing little more than holding our own."  The Department of Defense was furious that Lodge and the State Department were contradicting previous reports by Generals Taylor and Harkins.
 * 22 October

Ambassador Lodge cabled Washington saying "We should not thwart a coup for two reasons. First, it seems at least an even bet that the next government would not bungle and stumble as much as the present one has."
 * 25 October

Vietnamese coup plotter General Tran Van Don met with Colonel Lucien Conein of the American Embassy in Saigon. Don said that he had assurances from Ambassador Lodge that Conein was the proper channel to discuss coup plans. Don said that he and his fellow Generals wished to do everything possible to avoid American involvement in the coup. He stated emphatically that other Americans should quit talking about the coup with ARVN officers.
 * 28 October

Washington cabled request for Ambassador Lodge, through Colonel Conein, to get additional information about the upcoming coup in South Vietnam. The U.S. position was that the "burden of proof must be on coup group to show a substantial possibility of quick success; otherwise, we should discourage them from proceeding since a miscalculation could result in jeopardizing U.S. position in Southeast Asia."
 * 29 October

Ambassador Lodge responded to Washington's request for more information about coup plans by saying that the U.S. did "not have the power to delay or discourage a coup." He agreed that "a miscalculation could jeopardize" the U.S. position in Southeast Asia but added "We also run tremendous risks by doing nothing." Lodge noted that General Harkins did not concur with his opinion. Harkins had previously expressed opposition to a coup against Diem.
 * 30 October

A telegram from Washington to Ambassador Lodge took exception to his view that the U.S. could not delay or discourage a coup, but instructed him to discourage a coup unless in his judgement it had a good chance of success. The instruction stated that "It is not in the interest of USG to be or appear to be either the instrument of the existing government or the instrument of coup...But once a coup under responsible leadership has begun, and within these restrictions, it is in the interest of the U.S. Government that it should succeed.
 * 30 October

November


General Harkins notified Washington that the coup d'état against the Diem government was underway.
 * 1 November

The arrest and assassination of Ngo Dinh Diem and his younger brother Ngo Dinh Nhu marked the culmination of a successful coup led by General Duong Van Minh. Diem and Nhu were arrested and then killed in an armoured personnel carrier by ARVN officers.
 * 2 November

Ambassador Lodge was authorized by the State Department to release funds for aid projects to the new Government of Viet Nam. The funding of the projects had been frozen by the U.S. to pressure the Diem government to undertake reforms.
 * 2 November

President Kennedy sent a letter to Ambassador Lodge congratulating him for his work in Saigon.
 * 6 November

North Vietnam said that the Kennedy Administration had sanctioned the coup against President Diem because he failed to crush the Viet Cong rebellion. Diem had been too independent and Washington replaced him with a more pliable leader to gain control over South Vietnam.
 * 11 November

President Kennedy's plans to withdraw 1,000 American soldiers from Vietnam became public. General Charles Timmes announced the plan in Saigon.
 * 16 November

Secretary McNamara met with military and civilian leaders in Hawaii. The assessment of the progress of the war in South Vietnam was much more negative than in previous Hawaii meetings. The plan to withdraw 1,000 soldiers became "an accounting exercise" in which the replacement of personnel was slowed down to reduce temporarily the number of American military personnel in Vietnam. Of the combat troops, only one platoon (about 50 men) of Marines was to be withdrawn. A new National OPLAN 34-63 authorizing covert operations against North Vietnam was also approved at the meeting.
 * 20 November

National Security Action Memorandum 273 was drafted by McGeorge Bundy in Washington to reflect the more pessimistic view of the war coming out of the Hawaii meeting. President Kennedy apparently never saw the draft nor discussed its contents.
 * 21 November

President Kennedy was assassinated in Dallas, Texas. Lyndon B. Johnson becomes President of the U.S.
 * 22 November

The Central Committee of the Communist Party of North Vietnam met in emergency session to consider the implications of the fall of the Diem government. First Secretary Le Duan made a fiery speech saying "We are strong, while the enemy is weak...the strategy of revolution should not be a defensive one." Rather an offensive strategy should be adopted "to smash one by one the war policies of imperialism heading by the United States until its war plans are completely smashed." Le's speech won the approval of the members of the Central Committee who had previously been cautious about helping the Viet Cong and pursuing an aggressive policy in South Vietnam. Ho Chi Minh, a moderate, reportedly removed himself from the debate.
 * 22 November

The Battle of Chan La was a battle of the Vietnam War. The assault by Viet Cong forces was one in a series of attacks since the battle of Ap Bac back in January.
 * November 23

In the Battle of Hiep Hoa a Special Forces CIDG base was overrun in Hau Nghia on the Plain of Reeds (Dong Thap Muoi) west of Saigon. Five hundred Viet Cong attacked the base, manned by 5 U.S. Special Forces soldiers and 200 local militia. One of the Americans was wounded and the other four went missing, one of whom, Isaac Camacho, became the first American to escape from Viet Cong captivity. Forty-one of the local militiamen were killed. This was the first U.S. special forces base to be captured by the Viet Cong.
 * 24 November

President Johnson held his first meeting on Vietnam with senior advisers, the same group with whom former President Kennedy had often met. According to accounts, Johnson was aggressive at the meeting. "I am not going to lose Vietnam" he reportedly said and told Ambassador Lodge to tell the generals heading the government in South Vietnam that "Lyndon Johnson intends to stand by our word." He also reportedly said that he had "never been happy with our operations in Vietnam" and the "serious dissension and divisions" within the U.S. government.
 * 24 November

Johnson approved National Security Action Memorandum 273 (NSAM 273). The NSAM affirmed the U.S, commitment of helping South Vietnam "win their contest against he externally directed and supported Communist conspiracy." There was one major substantive change in the text drafted by McGeorge Bundy on November 21. Kennedy had previously agreed with South Vietnamese covert attacks against North Vietnam; the newly drafted paragraph 7 in the NSAM called for "prompt submission of plans" for covert U.S. attacks on North Vietnam.
 * 26 November

Regarding Kennedy's plan for the withdrawal of 1,000 U.S. soldiers by the end of 1963, the NSAM said only, "The objectives of the United States with respect to the withdrawal of U. S. military personnel remain as stated in the White House statement of October 2, 1963." (See above)

December
The South Vietnamese government suspended the Strategic Hamlet Program, effectively ending it. A U.S. AID official reported that three-fourths of the Strategic Hamlets in Long An province had already been destroyed by the Viet Cong or the inhabitants themselves.
 * 2 December

Senator Mike Mansfield, considered Congress's expert on Southeast Asia, wrote a memo to President Johnson suggesting that a neutral Vietnam be negotiated. Mansfield disagreed with Johnson's other advisers "that the war can be won at a limited expenditure of American lives and resources somewhere commensurate with our national interests in south Viet Nam."
 * 7 December

Secretary of Defense McNamara cabled Ambassador Lodge that he was coming to visit South Vietnam "to make clear to North Vietnam that the U.S. will not accept a communist victory in South Vietnam and we will escalate the conflict to whatever level is required to insure their defeat."
 * 12 December

McNamara in South Vietnam requested to visit a district of the country in which the former Diem government of South Vietnam claimed 18 strategic hamlets were located; he discovered than none of the 18 existed. McNamara had gone from being optimistic about the progress of the war in October to pessimistic in December.
 * 18 December

John McCone Director of the CIA said, "It is abundantly clear that statistics received over the last year or more from the GVN [Government of Vietnam] officials and reported by the US mission on which we gauged the trend of the war were grossly in error.
 * 21 December

Secretary of Defense McNamara said that, “Current trends [in South Vietnam], unless reversed in the next 2–3 months, will lead to neutralization at best and more likely to a Communist-controlled state.” He said that the U.S. must "give the Viet Cong and their supporters early and unmistakable signals that their success is a transitory thing."
 * 21 December

One hundred and twenty-two American soldiers were killed in the Vietnam War in 1963. 16,300 U.S. military personnel were in South Vietnam at the end of the year
 * 31 December

North Vietnam had infiltrated about 40,000 cadres and fighters into South Vietnam over a period of several years. They made up about 50 percent of the Viet Cong army and 80 percent of political operatives and technical personnel. They consisted mostly of southerners who had migrated north in 1954-1955 to reside in a communist state rather than remain in South Vietnam. Units of the North Vietnamese army had not yet been dispatched to South Vietnam.