September 1964 South Vietnamese coup attempt Before dawn on September 13 , 1964 , the ruling military junta of South Vietnam , led by General Nguyen Khanh , was threatened by a coup attempt headed by Generals Lam Van Phat and Duong Van Duc , who sent dissident units into the capital Saigon . They captured various key points and announced over national radio the overthrow of the incumbent regime . With the help of the Americans , Khanh was able to rally support and the coup collapsed the next morning without any casualties . In the immediate month leading up the coup , Khanh ' s leadership became increasingly troubled . He had tried to augment his powers by declaring a state of emergency , but this only provoked large - scale protests and riots calling for an end to military rule , with Buddhist activists at the forefront . Fearful of losing power , Khanh began making concessions to the protesters and promised democracy in the near future . He also removed several military officials closely linked to the discriminatory Catholic rule of the slain former President Ngo Dinh Diem ; this response to Buddhist pressure dismayed several Catholic officers , who made a few abortive moves to remove him from power . In part because of pressure from Buddhist protests , Khanh removed the Catholics Phat and Duc from the posts of Interior Minister and IV Corps commander , respectively . They responded with a coup supported by the Catholic - aligned Dai Viet Quoc Dan Dang , as well as General Tran Thien Khiem , a Catholic who had helped Khanh to power . Having captured the radio station , Phat then made a broadcast promising to revive Diem ' s policies . Khanh managed to evade capture and , during the first stage of the coup , there was little activity as most senior officers failed to support either side . Throughout the day , Khanh gradually rallied more allies and the US remained supportive of his rule and pressured the rebels to give up . With the backing of Air Marshal Nguyen Cao Ky , commander of the Vietnam Air Force , and General Nguyen Chanh Thi , Khanh was able to force Phat and Duc to capitulate the next morning , September 14 . Duc , Ky and Thi then appeared at a media conference where they denied that any coup had taken place and put on a choreographed display of unity , claiming that nobody would be prosecuted over the events . Convinced that Khiem was involved in the plot , Khanh had him exiled to Washington as ambassador , and eased General Duong Van Minh out of the political scene , thereby removing the other two nominal members of the ruling triumvirate . However , concerned that Ky and Thi had become too powerful , Khanh had Phat and Duc acquitted at their military trial in an attempt to use them as political counterweights . Despite his survival , the coup was seen by the historian George McTurnan Kahin as the start of Khanh ' s ultimate political decline . Due to the intervention of Ky and Thi , Khanh was now indebted to them , and in an attempt to maintain his power in the face of increasing military opposition , he tried to court support from Buddhist civilian activists , who supported negotiations with the communists to end the Vietnam War . As the Americans were strongly opposed to such policies , relations with Khanh became increasingly strained and he was deposed in February 1965 with US connivance . Background . General Nguyen Khanh had come to power in January 1964 after surprising the ruling junta of General Duong Van Minh in a pre - dawn operation , taking control without firing a shot . Because of American pressure , he retained the popular Minh as a token head of state , while holding the real power by controlling the Military Revolutionary Council ( MRC ) . In August , the Vietnam War expanded with the Tonkin Gulf incident , a disputed encounter between North Vietnamese and American naval vessels ; Washington accused the communists of launching an attack in international waters . Khanh saw the tense situation as an opportunity to increase his power . On August 7 , he declared a state of emergency , giving the police the ability to search properties under any circumstances , ban protests and arbitrarily jail " elements considered as dangerous to national security " . He further enacted censorship to stop " the circulation of all publications , documents , and leaflets considered as harmful to public order " . Khanh produced a new constitution , known as the Vung Tau Charter , which would have augmented his personal power at the expense of the already - limited Minh . However , this only served to weaken Khanh as large demonstrations and riots in the cities broke out — with the majority Buddhists prominent — calling for an end to the state of emergency and the new constitution , as well as a progression back to civilian rule . Fearing he could be toppled by the intensifying protests , Khanh met with Buddhist leaders . They asked him to repeal the new constitution , reinstate civilian rule , and remove Can Lao Party — a secret Catholic body used by former President Ngo Dinh Diem to infiltrate and control all aspects of society — members from power , and Khanh agreed . General Tran Thien Khiem claimed " Khanh felt there was no choice but to accept since the influence of Tri Quang was so great that he could not only turn the majority of the people against the government but could influence the effectiveness of the armed forces . " Khanh publicly promised to reformulate the Vung Tau Charter , allow protests and liberalize the press . This encouraged more demonstrations by activists , and Khanh responded with wider concessions . Under the new arrangements , the new constitution would be repealed , and the MRC would disband . Khanh also promised to create an elected legislature within a year . Many senior officers , particularly the Catholic Generals Khiem and Nguyen Van Thieu , decried what they viewed as a handing of power to the Buddhist leaders . They tried to remove Khanh in favor of Minh , and recruited many officers to their plot . Khiem and Thieu sought out US Ambassador Maxwell Taylor for a private endorsement of their plan , but Taylor did not want any more changes in leadership , fearing a corrosive effect on the already - unstable government . This deterred Khiem ' s group from acting on their plans . The division among the generals came to a head at a meeting of the MRC on August 26 – 27 . Khanh said the instability was due to troublemaking by members and supporters of the Catholic - aligned Dai Viet Quoc Dan Dang ( Nationalist Party of Greater Vietnam ) , whom he accused of putting partisan plotting ahead of the national interest . Prominent officers associated with the Dai Viet included Thieu and Khiem . Khiem blamed Khanh ' s weakness in dealing with Buddhist activists for the demonstrations in the cities and the rural losses to the communists . Thieu and another Catholic General Nguyen Huu Co called for the replacement of Khanh with Minh , but the latter refused . Minh claimed that Khanh was the only one who would get funding from Washington , so they should support him , prompting Khiem to angrily say " Obviously , Khanh is a puppet of the US government , and we are tired of being told by the Americans how we should run our internal affairs . " Feeling pressured by the strong condemnations of his colleagues , Khanh promised to resign , but no replacement was agreed upon and another meeting was convened . After more arguing between the senior officers , they agreed that Khanh , Minh , and Khiem would rule as a triumvirate for two months , until a new civilian government could be formed . However , because of their disunity , the trio did little . Khanh dominated the decision - making and sidelined Khiem and Minh . The US military commander in Vietnam William Westmoreland deplored the concessions Khanh made to political opponents and lobbied Washington for permission to attack North Vietnam , saying that Khanh could not survive without it . Coup . At the start of September 1964 , General Lam Van Phat was dismissed as Interior Minister , while General Duong Van Duc was about to be removed as IV Corps commander . Both were removed partly due to pressure from Buddhist activists , who accused Khanh of accommodating too many Catholic Diem supporters in leadership positions . Diem had tried to use the loyalist Phat to help thwart the November 1963 coup , but the rebels managed to sideline Diem ' s general and execute the president . Disgruntled by their demotions , Phat and Duc launched a coup attempt before dawn on September 13 , having recruited ten army battalions . They gained the support of Colonel Ly Tong Ba , the head of the 7th Division ' s armored section , and Colonel Duong Hieu Nghia , a tank commander who had been one of Diem ' s assassins . It appeared at this stage that the coup was supported by Catholic and Dai Viet elements . Another member of the conspiracy was Colonel Pham Ngoc Thao , who while a Catholic , was a communist spy trying to maximize infighting at every possible opportunity . Duc and Phat ' s plot was supported during the planning phase by Defense Minister and triumvirate member Khiem . General Huynh Van Cao , a Catholic and Diem loyalist while the former president was alive , claimed in a 1972 newspaper interview that Khiem — by then prime minister — had asked him to join the coup . Cao said he had declined Khiem ' s invitation , mildly mocking him by asking " You ' re part of the ' Troika ' now . . . won ' t you be overthrowing yourself ? " Cao said he had pointed out that political upheaval in Saigon would be a bad idea because Vietnam was prominent during the ongoing US presidential election campaign and negative publicity could lead to a decrease in American public and political support for South Vietnam . Four battalions of rebel troops moved before dawn from the Mekong Delta towards Saigon , using armored personnel carriers and jeeps carrying machine guns . After cowing several police checkpoints on the edge of the capital with threats of machine - gun and artillery fire , the plotters put rebel sentries in their place to seal off Saigon from incoming or outgoing traffic . They then captured communication facilities in the capital , including the post office , to prevent messages from being sent in or out . As his troops took over the city , Phat sat in a civilian vehicle and placidly said " We ' ll be holding a press conference in town this afternoon at 4 p . m . " He said " This is nothing to worry about . Just a little operation against some politicians . " The rebels set up their command post in the Saigon home of General Duong Ngoc Lam , who had been removed from his post as Mayor of Saigon by Khanh . Lam had commanded the Civil Guard during Diem ' s presidency and was one of his trusted supporters . The rebels took over the city without any gunfire , and used the national radio station to make a broadcast . Claiming to represent " The Council for the Liberation of the Nation " , Phat proclaimed a regime change , and accused Khanh of promoting conflict within the nation ' s military and political leadership . He promised to capture Khanh and pursue a policy of increased anti - communism , with a stronger government and military . Phat said he would use the ideology and legacy of Diem to lay the foundation for his new junta . Duc claimed the coup attempt was prompted by " the transfer to the capital of some neutralist elements , and by some pro - communists in the government " . According to the historian George McTurnan Kahin , Phat ' s broadcast was " triumphant " and may have prompted senior officers who were neither part of the original conspiracy nor fully loyal to Khanh to conclude that Phat and Duc would not embrace them if they abandoned Khanh . In contrast to Phat ' s serene demeanor , his incoming troops prompted devotees at the Catholic cathedral — who were attending mass — to run away in fear . The Buddhists however , made no overt reaction to the pro - Diem coup , even though the former president had pursued policies that discriminated against them . There was little reaction from most of the military commanders . The Vietnam Air Force commander Air Marshal Nguyen Cao Ky had promised a fortnight earlier to use his aircraft against any coup attempt , but he took no action early in the morning . At the same time , Khiem and Thieu ' s lack of public action was seen as implicit support for the coup , as their criticism of Khanh ' s leadership in junta meetings and private attempts to remove him were well - known . A US Embassy report to the State Department during the coup described Thieu and Khiem as being " so passive that they appear to have been either tacitly supporting or associated with this move by Duc and Phat " . Some time later , Ky called in troops serving on Saigon ' s outskirts to come to Tan Son Nhut Air Base , the largest in the country and the headquarters of the military . He barricaded the soldiers into defensive positions and vowed a " massacre " if rebels attacked the base . A stand - off ensued between rebel tanks and loyalist troops around the perimeter of the base , but it petered out without any violence after the rebels stepped back . Ky had apparently been angered by comments made by a rebel source who claimed that he was part of the coup attempt . Ky was also well known for his hawkish attitude and close relations with the American military presence in Vietnam , and US opposition to the putsch was thought to have been quickly conveyed to him . Phat and Duc could not apprehend Khanh , who had escaped the capital and flown to the central highlands resort town of Da Lat . Their forces stormed Khanh ' s office and captured his duty officers but could not find the junta leader . There was then a lull in the movement of troops and units . One Vietnamese public servant said that " All these preparations are the result of a big misunderstanding on both sides . I don ' t think either group will start anything , but both think the other will . " Taylor was on an emergency flight from Honolulu — where he had been in meetings with senior American military figures — back to Saigon and he said the coup " certainly was unannounced and unheralded . " In the mid - afternoon Khanh made a radio broadcast on a loyalist system , condemning the coup and calling on the military to remain loyal , claiming that support for the " rebellious leaders " would play into the hands of the Vietcong . US intervention . Some US advisers serving with units involved in the coup were driven off by rebel officers who did not want interference . The plotters thought the Americans would disapprove of their actions , as Taylor had recently talked of an " upward trend " in the war against the communists , while President Lyndon Johnson praised the " continued progress " against the Vietcong . During the early hours of the coup , officials in Washington remained guarded in public , saying they were monitoring the situation and calling for calm , without explicitly supporting either side . Despite this , they did hint at a preference for the status quo : " hope that consultations among the leadership will shortly permit the Government to restore the situation in the city to normal " . Behind the scenes , they used the respective American military advisers to lobby unit leaders against participating in the coup . US officials flew after Khanh to encourage him to return to Saigon and reassert his control . The general refused to do so unless the Americans publicly announced their support for him . The Americans then asked Khanh about his plans for the future , but felt that his answers betrayed a lack of direction . After talking to Phat and Duc , they concluded the same , so they decided to back the incumbent and made a press release through the embassy endorsing Khanh . Their decision was augmented by the rebels ' inability to land a decisive blow , making the Americans more favorable to a continuation of Khanh ' s rule . The Voice of America broadcast a message emphasizing ongoing US support for Khanh and opposition to the coup . It said the Americans had been monitoring the situation closely and that the incumbent regime was functioning ; it further said : At the same time , anonymous US sources told journalists that the coup was concerning even if it failed , due to its destabilizing effects . Khanh also requested to General William Westmoreland , the commander of American forces in Vietnam , that US Marines come to his aid , and called for the Americans to formulate a " counter - plan " for him . Although no US forces made landfall , marines were placed just offshore near Saigon and Da Nang in readiness . Coup collapse . The US announcement of support for Khanh helped to deter ARVN officers from joining Phat and Duc , who decided to give up . Westmoreland had spoken to Duc and reported to Washington that he " in no uncertain terms . . . informed him [ Duc ] that MACV , the U . S . Mission , and the U . S . Government did not support in any way his move , [ and ] advised that he get his troops moved out of town [ Saigon ] immediately . He said that he understood and thanked me . He seemed to be a shaky and insecure young man . " Duc mistakenly thought that Ky and his subordinates would be joining the coup , but he later realized his misjudgement . When he found out he had been tricked into thinking the plotters had great strength , he gave up . According to an anonymous source , Duc was alarmed by Phat ' s strong statements during his radio broadcast , which made him reconsider his participation in the coup . Brigadier General Nguyen Chanh Thi of the 1st Division also supported Khanh . A CIA log of the coup proceedings said Thieu and Khiem " issued expressions of firm support for Khanh somewhat belatedly " . Ky then decided to make a show of force as Phat and Duc began to wilt , and he sent jets to fly low over Saigon and finish off the rebel stand . They circled continuously but never actually fired . He also sent two C - 47s to Vung Tau to pick up two companies of South Vietnamese marines who had remained loyal to Khanh . Several more battalions of loyal infantry were transported into Saigon . Phat then withdrew with his forces to My Tho , the base of the 7th Division . In the early hours of September 14 , before dawn , Ky met senior coup leaders after inviting them to Tan Son Nhut and told them to back down , which they did . Loyalist forces regained control of the radio station and broadcast an announcement claiming control and ordering students and public servants to go about their normal lives . In the meantime , air force planes continued to set off flares to show their alertness , and rocket launchers and more weapons were deployed around Tan Son Nhut . Three battalions of paratroopers were brought in to patrol the airfield ' s perimeter . Media conference . As the coup collapsed , Ky and Duc appeared with other senior officers at a news conference where they proclaimed that the South Vietnamese military was united . They announced a resolution by the armed forces , signed by them and seven others , claiming a united front against corruption . Apart from Ky and Duc , the other seven signatories were Thi , General Cao Van Vien , an airborne brigade commander , the commander of I Corps General Ton That Xung , the commander of the Marine Brigade General Le Nguyen Khang , General Nguyen Duc Thang of the General Staff , the commander of the Republic of Vietnam Navy Admiral Chung Tan Cang , and the commander of the Rangers Colonel Pham Xuan Nhuan . The officers claimed the events in the capital were misinterpreted by observers , as " there was no coup " . Ky said Khanh was in complete control and that the senior officers involved in the stand - off " have agreed to rejoin their units to fight the Communists " , naming Duc , Phat , Lam and commander of the 7th Division Huynh Van Ton . Duc claimed that the leading officers had agreed : Duc further commented that fair treatment of citizens was the only way to defeat the communists . When asked if he now supported Khanh , Duc , " looking ill with weariness , if nothing else " , simply nodded in agreement . Ky also claimed that no further action would be taken against those who were involved with Duc and Phat ' s activities . After Khanh was again secure in Saigon , he said " I am very moved by the spirit of unity shown by the armed forces and population when faced with the threat of internal strife . I commend the patriotism of all the soldiers who knew how to put the higher interests of the nation above all else . " Khanh said he would relinquish power and return to a purely military rule in two months time , but reneged on an earlier explicit promise to guarantee a purely civilian government , simply stating that the new regime would be one " that has the confidence of the entire people " . The Soviet Union said the coup " demonstrated once again on what a rotten foundation Washington ' s policy in South Vietnam is based " . Arrests . Despite Ky and Duc ' s media event , it appeared that Phat and Ton were remaining defiant after returning to the latter ' s 7th Division ' s headquarters in My Tho . Ton was apparently still maintaining a hostile political stance , and threatening to break away from the Saigon regime by overseeing the area around My Tho as a virtual independent state . Ton was reported to have threatened to cut the main highway from Saigon into My Tho and further south into the rest of the Mekong Delta , although it was thought he had no intention or means of assaulting Saigon militarily . Ky said a helicopter had been sent to arrest Ton but that a stand - off had developed . However , on September 16 Khanh had the plotters taken into custody . Duc , the rebel tank commander Nghia , Ton , and Lam were all arrested , followed by Phat , who returned to Saigon to turn himself in . A trial was then scheduled . Khanh removed three of the four corps commanders and six of the nine division commanders for failing to move against Phat and Duc . Power shift . Ky and Thi ' s role in putting down the coup attempt gave them more leverage in Saigon ' s military politics . Indebted to Ky , Thi , and the youthful clique of officers dubbed the Young Turks for helping him stay in power , Khanh was now in a weaker position . Ky ' s group called on Khanh to remove " corrupt , dishonest and counterrevolutionary " officers , civil servants and " exploitationists " , and threatened to remove him if he did not enact their proposed reforms , as " the people and the armed forces will be compelled to make a second revolution " . This was interpreted as a thinly veiled warning to Khanh that the younger officers were intent on holding significant power through the military apparatus , contrary to any plans for civilian rule . Ky specifically said nine or ten other officers should be dismissed for involvement in the coup , but refused to identify who he had in mind . Some observers accused Ky and Thi of deliberately orchestrating or allowing the plot to develop before putting it down in order to embarrass Khanh and allow themselves to gain prominence and prestige on the political stage . In later years , Cao Huy Thuan , a professor and Buddhist activist based in the northern town of Da Nang , claimed that during a meeting with Ky and Thi a few days before the coup , the officers had discussed their plans for overthrowing Khanh . Another conspiracy claim was propagated by General Tran Van Don , who conjectured that Khanh had tried to provoke or bait rival generals , such as Khiem , into revolting against him so he could defeat and remove them from the scene , thereby strengthening himself and boosting his political image . The communists were pleased by the coup , as the South Vietnamese military was wasting its resources and energy on infighting . They did not make any attacks in the days immediately after the coup as they were worried their doing so might galvanize the divided society into action against a common cause . Retribution and trial . Following the coup , Khanh concluded that his triumvirate partner Khiem had played a major role in fomenting the coup and insisted he be sent out of Saigon . The Americans agreed and Ambassador Taylor organized for Khiem to be made Saigon ' s representative in Washington . Soon after , Thao was dispatched to join Khiem as his press attaché . During the coup , Minh had remained aloof from the proceedings , angering Khanh and keeping their long - running rivalry going . By the end of October , the Johnson administration had become more supportive of Taylor ' s negative opinion of Minh and concluded that US interests would be optimized if Khanh prevailed in the power struggle . As a result , the Americans eventually paid for Minh to go on a " good will tour " so he could be pushed off the political scene without embarrassment . In the middle of October , Phat and 19 others were put on trial in a military court ; observers predicted Phat would be the only one to face the death penalty , and that this would be reduced to a custodial term . Of the accused , 7 were civilians and 13 were military officers . They tried to appear confident and waved to family and friends . Duc told the assembled media the trial was unfair , stating " I believe in the supreme court of conscience " . He then pointed to his subordinate officers and called them " national heroes " . He denied media speculation he had backed down during the coup to avoid being bombed by Ky , claiming " I wanted to avoid bloodshed . . . I am very proud of my decision " . Phat ' s lawyers started by asking for the charges against the conspirators to be dismissed , claiming the rebels had not been captured " red - handed " , but this request was denied . They were more successful in another demand , managing to persuade the five military judges to allow witnesses to be called . The court agreed to their request to compel Khanh , Ky and the civilian Deputy Prime Minister Nguyen Xuan Oanh to appear before the hearing . The accused officers claimed to have only intended to make a show of force , rather than overthrow Khanh . Duc claimed that the objective of his actions was to " emphasize my ideas " and said his actions did not constitute a coup attempt . Duc said that if he was intending to overthrow the government , he would have arrested public servants or military officials and denied having done so . On the other hand , he also admitted to being concerned by Khanh ' s policies . Duc said he had decided to end what he regarded as a military protest demonstration when Khanh promised to consider his concerns , and then returned to the IV Corps headquarters in the Mekong Delta . He claimed responsibility for the actions of his subordinate and co - accused , Colonel Ton , who led the 7th Division of IV Corps into Saigon . Ton agreed that Duc had ordered him to move his troops into the capital . During questioning , Duc did not refer to his coup partner Phat . Asked why he had denounced Khanh as a " traitor " in a radio broadcast during the coup attempt , Phat said he had merely " gotten excited " . Phat was asked about the collapse of his coup attempt and he discussed his visit to the American Embassy along with labor union leader Tran Quoc Buu on the evening of September 13 . He said his discussion with Deputy Ambassador U . Alexis Johnson was " not too important " and played down its impact , claiming that Johnson ' s perfunctory use of French had limited any talks he would have wanted to have . This was contradicted by Buu , who told journalists that the discussion with Johnson had lasted for around 90 minutes . Of the civilians arrested , Buu was the most prominent . He was accused of involvement in trying to overthrow the regime because he had been involved in the meeting between Phat and Johnson . Buu acknowledged that he organized the meeting but said he was not involved in any plans for a leadership change . He claimed that US Embassy officials had phoned him during the coup to ask him to order his union members to refrain from agitating on industrial relations matters during the physically dangerous period . He said he then offered to arrange a meeting for the Americans with the coup leaders to see if a non - violent solution to the stand - off could be found . Buu said he was not acting in a partial manner and did not listen to Johnson ' s discussion with Phat . The Americans agreed with Buu ' s claims and privately thought he had been arrested for staging labor union activities and demonstrations unrelated to the military power struggle . One week later , on October 24 , the charges were dropped . Khanh then gave Duc and Phat two months of detention for indiscipline ; their subordinates were incarcerated for shorter periods . According to Kahin , Khanh rigged the military trial so that Duc and Phat were acquitted so they could be used as a Catholic counterweight to the Young Turks faction of Ky and Thi , who in Khanh ' s eyes had become increasingly strong and ominous . Khanh also tried to build an alliance with the " Da Lat Generals " — so - called as he had put them under house arrest there after toppling them in the January 1964 coup — by recalling them to active roles . On November 14 , Khanh brought back Don as the deputy chief of staff , and installed fellow Da Lat General Ton That Dinh as his assistant . However , the Young Turks were cognizant of Khanh ' s motives , and continued to pressure him to sideline Don and Dinh in an attempt to gain more power for themselves . For his part , realizing his political base within the junta was precarious , Khanh had to seek more popular support . According to Kahin , " in what was strictly a marriage of convenience " , Khanh had to try to ameliorate the only large civilian political force in South Vietnam , the Buddhist activists , who publicly called for a negotiated end to the war . This was regarded by Kahin as the start of Khanh ' s ultimate political downfall , as the Americans were resolutely opposed to any coexistence with the communists and their relations with Khanh declined steadily from then onwards . In December , Khanh and Taylor had an angry exchange after the junta dissolved the consultative High National Council , leading both men to call for the other to leave the country and prompting Khanh to repeatedly denounce the ambassador in the media . Khanh was eventually deposed in February 1965 by Ky and Thi with the backing , encouragement and some organizational help from the Americans .