Plot Against Diem In A House Divided: Washington, Langley, Saigon

2025-05-22 08:11:25

(MENAFN- Asia Times) These materials are reproduced from with the permission of the National Security Archive.

Washington, DC, May 22, 2025 – Early in the morning of October 7, 1963, the top leadership of the Central Intelligence Agency (CIA) gathered in the office of the director of central intelligence (DCI) to discuss the brewing crisis in South Vietnam and America's role in it.

DCI John McCone warned his colleagues:“Under no circumstances” should“the Agency get into the subject of assassination or other highly sensitive matters with [US Ambassador Henry Cabot] Lodge.” The Ambassador had“no concept of security,” McCone added, and tended to use the press to enhance his power, presumably at the expense of the CIA, according to a recently declassified account of the meeting published today by the National Security Archive (Document 9).[1]

Twenty-six days later, South Vietnamese President Ngo Dinh Diem and his brother, Ngo Dinh Nhu, were executed as part of a military coup d'état that would further destabilize the Southeast Asian country for years to come.

In the years since, the extent of the US role in the coup and assassination has been hotly debated and disputed. For over two decades, the late John Prados shed light on the Kennedy administration's position toward the Diem coup in a series of National Security Archive Electronic Briefing Books.[2]

This new EBB supplements those publications with recently declassified documents obtained through the Freedom of Information Act (FOIA), the JFK Assassination Files, the Gerald R. Ford Presidential Library, and the personal papers of George McTurnan Kahin, a prominent scholar on Southeast Asia and early critic of the Vietnam war.[3]

It highlights the role of key CIA players – McCone, CIA Far East Division Chief William Colby, CIA Saigon Chief of Station John H. Richardson and contract officer Lucien Conein – and provides new details on how the coup emerged, almost organically, despite indecision, divisions between the leading agencies and bitter rivalries among the individual officials in charge.

With Colby and McCone opposed to the coup, Conein, who was trusted by Lodge and keen to follow the ambassador's orders, became the key player on the ground.

From the very beginning, government secrecy, obfuscation, lies, and the incomplete and contradictory statements of key American participants confused the record.[4]

Less than two weeks after the coup against Diem, and on the day that President John F. Kennedy was assassinated, McCone – joined by Colby – told the President's Foreign Intelligence Advisory Board (PFIAB) that the CIA“had no part in organizing the coup” and“did not have information on and does not know about the assassinations of Diem and Nhu,” according to a document that was fully declassified for the first time this year as part of the final JFK assassination documents release (Document 18).

Yet, a dozen years later, Colby, then the DCI and speaking to congressional investigators, expressed a more introspective tone and acknowledged the Agency role:“I think when you support a coup through violent overthrow you have to understand that you are taking responsibility for people getting killed. Soldiers got killed and the head of the other side [Diem] got killed.”[5]

Additional documents declassified last year under the FOIA, including a detailed CIA chronology of the entire episode, show that the US encouraged the coup plotters to take“the earliest possible action” and provided assurances, money and other support that together“constituted a clear call for action” (Documents 7 and 19).

By the late summer of 1963, as meetings between the CIA's Lucien Conein and the plotting South Vietnamese generals continued, Washington had settled, based on Ambassador Lodge's recommendations, on a position of“not thwarting” a coup, according to a document released earlier this year in response to a FOIA request from the National Security Archive (Document 8).

Langley also instructed Conein to review the generals' plans, with the exclusion of any assassination plots. The US also promised that military aid would continue once the generals had removed the Diem regime.

Caught off guard as the coup started, having received a much shorter warning than anticipated, Conein handed over the rough equivalent of $68,000 in bribes“to reward opposition military units who joined the coup group,” according to a now declassified report from the CIA Inspector General (Document 19, below)), and sent frequent reports to Saigon and Langley from the Generals' headquarters (Document 17).

Document 19 – Fully declassified CIA Inspector General report provides new details on US government role in coup against Diem

This newly available historical evidence shows that the US was deeply involved with the key players who would ultimately overthrow and kill Diem and his brother, up to and including the day of the coup. While Colby and McCone were clearly opposed to the coup and made the strongest arguments against it, the senior CIA officials were overruled by the president and outmaneuvered by Lodge.

In the end, they and their CIA colleagues“faithfully carried out instructions” to support the coup-plotting generals, according to a long-awaited and now fully declassified CIA Inspector General report on the episode (Document 19).[6]

Other notable documents published today include:

An August 30 telegram from a CIA Saigon Station officer (likely Conein) reporting on an explicit discussion among the coup-plotting South Vietnamese generals about the need to assassinate President Diem for the success of the regime-change operation (Document 3).
Reports providing additional details on Langley's initial reluctance to overthrow Diem – partly due to the Agency's long-standing relationship with his brother Ngo Dinh Nhu (Documents 4, 6, and 13).
Documents showing that the US Embassy in Saigon was mired in dysfunction and mistrust, with Lodge blaming CIA Chief of Station John Richardson for the August coup failure and Richardson finding Lodge too gung-ho and untrustworthy (Documents 6 and 7).
Records on McCone and Colby's growing distrust of, and contempt for, Ambassador Lodge, culminating in their failed opposition to replacing Richardson as CIA Chief of Station (Document 9).
The fully declassified CIA personnel file on Lucien Conein-who would be awarded the CIA's“intelligence star” for his efforts during the South Vietnamese crisis of 1963-suggests he played a more prominent role than previously acknowledged (Document 22).
A document found among the personal papers of George McTurnan Kahin suggesting a new version of – and a new rationale for – the South Vietnamese generals' decision to murder Diem and Nhu: that, if they survived, Washington might change its mind and reinstate them in power (Document 23).

Vietnam President Ngo Dinh DiemThe failed August coup

When the US government desires the overthrow of a foreign government, the ideal scenario for policymakers is that the US plays a minimal, deniable role, and that the government speaks with one voice. Part of the challenge in ascertaining the degree of US involvement in the overthrow and assassination of Ngo Dinh Diem – aside from secrecy – is the fact that the Kennedy administration's position toward the South Vietnamese president in the summer and fall of 1963 was marked by division, indecision, oscillation, distrust and bureaucratic chicanery.

In retrospect, the fate of Diem and his brother, Ngo Dinh Nhu, was sealed during the“Buddhist Crisis” of May 1963. On June 11, the images of the self-immolation of Buddhist Monk Thích Quang Duc in the name of religious freedom shocked the world and focused attention – including in Washington, DC – on the autocratic, repressive, unstable and corrupt nature of Diem's regime.[7]

Diem and Nhu – the head of South Vietnam's secret police – began to be perceived as incapable of leading a united South Vietnam against the communist threat. By August 1963, several US officials had become so disgruntled with Diem, especially in the White House and State Department, that they began taking formal steps to create the conditions for a coup.

On August 24, Assistant Secretary of State for Far Eastern Affairs Roger A. Hilsman sent a now-infamous State Department telegram (deptel) No. 243 to Saigon (first published in National Security Archive EBB 302 of 2009). Deptel 243 asked the embassy to make clear to the Vietnamese military that the US would support a new interim government. The ambassador and the country team were asked to“urgently examine alternative leadership” and to make“detailed plans” on how to“bring about Diem's replacement if this should become necessary” (Document 19).

Two documents now confirm that the CIA played no role in drafting deptel 243 and was not consulted during the decision-making process. Instead, Deputy Director for Plans Richard Helms was only notified of the deptel once it had been cleared with“Hyannis Port,” that is, with President Kennedy (Documents 16 and 19).

US Ambassador to South Vietnam Henry Cabot Lodge

In Saigon, CIA Chief of Station John Richardson later reported that Lodge interpreted the telegram as marching orders to orchestrate a coup (Document 9).

Two days later, a CIA station telegram that was probably responsive to instructions from Washington further specified the position that the embassy and the station would take in their dealings with the coup plotters. Ambassador Lodge said the operation should be deniable; the US hand should not show. The telegram also contained nine points to guide the country team's approach to the generals. These included an agreement that Nhu had to go but also that the fate of Diem was up to the generals themselves.

The document confirmed the US posture of deniability, telling the generals:“Win or lose. Don't expect to be bailed out.” And yet, it also sets a clear system of incentives for the generals to proceed: Unless the Nhus were removed from power and the Buddhists were freed, the generals could expect an end to financial and military support (Document 1).

As the CIA team was getting ready to meet the generals based on these guidelines, the situation changed on August 29. In the morning, CIA Chief of Station Richardson, CIA contract agent Lucien Conein and CIA station officer Alphonse Spera were shown a telegram from General Maxwell Taylor to Military Assistance Command, Vietnam (MACV) Commander Paul Harkins. The telegram hinted that Washington had“second thoughts” regarding the coup (Document 7).

With a meeting with the Generals already scheduled, Richardson ordered Conein and Spera to proceed but to provide no iron-clad assurances regarding US support. Having met with the generals, the CIA reported to Washington that they had a“plan for a coup d'etat and will implement it when they are assured that the US government is fully behind them.”

As proof of support, the generals asked the US to cut aid to the South Vietnamese government. The suspension of aid would signal U.S. support and alter the balance of forces in Saigon against Diem.[8]

On the 30th, an exchange between the president and Lodge made clear that – while Washington had not completely changed its mind on a coup – Kennedy wanted to keep his options open until the last minute and support a coup only if it would be successful. As he told Lodge,“When we go, we must go to win, but it will be better to change our minds than to fail.”[9]

Lodge agreed with the president but also warned that – since this was primarily a Vietnamese affair – the U.S. government might not have the option to stop the coup once one was in motion.[10]

General Duong Van Minh – Also known as Big Minh, one of the coup leaders.

In the early afternoon of the 30th, the embassy in Saigon sent a telegram to the State Department. The telegram reported a conversation between a CIA CAS [controlled American source] officer (likely Conein) and Colonel Pham Ngoc Thao, who had recently attended a dinner with the plotting generals. Thao explained that Generals Tran Thien Khiem and Nguyen Khanh agreed to support General Duong Van Minh's coup, provided that Diem and Nhu were killed during the coup attempt.“Generals,” the document continued,“said that if first step of attempted coup is successful, i.e. the assassination of President Diem, they would then support the coup openly” (Document 3).

Document 3 – South Vietnamese Generals openly discuss assassinating Diem.

Half an hour later, the embassy reported with some apprehension that General Khiem, one of the main coup plotters, had been called to the Presidential Palace and had spent several hours there, while at the same time refusing to take US calls.[11] The coup seemed to be in peril.

By the following day, the coup had indeed petered out. The US government had refused to cut US aid as the generals had requested.[12] General Khiem also claimed that the Generals did not have a favorable balance of forces, an assessment Harkins agreed with.[13]

On September 10, during a PFIAB meeting, CIA director McCone expressed relief that the plan had been aborted (Document 4). He denied Vietnamese press allegations that the agency was behind efforts to remove Diem from power and said the plan to“unload the Nhus” (contained in deptel 243) was misguided. The decision to send such a telegram was the result of“miscalculation of the generals' true capabilities and intentions.” McCone reassured the Agency's overseers that such a policy was now on the backburner (Document 4).

John McCone, director of central intelligence.

In Saigon, though, the failure of the August coup became a main element of contention between the CIA, especially Richardson, and Lodge. The former believed that the coup had failed because the generals did not have the capabilities to carry it out, regardless of the extent of US assurances. In Richardson's assessment,“there was a clear distinction between our full encouragement and actually being in a position to put together the ingredients for a successful coup” (Document 7). Lodge, though, came to see Richardson and his unwillingness to explicitly support the generals as the main reason for the August coup failure (Document 7).

The Lodge-Richardson rift intensifies

In mid-September, Lodge started calling for Richardson to be replaced as chief of station by General Edward Lansdale. On September 18, the prospect was raised during a meeting among McCone, Secretary of State Dean Rusk, Secretary of Defense Robert McNamara, National Security Adviser McGeorge Bundy and Under Secretary of State for Political Affairs W. Averell Harriman (Document 5).

While no clear policy on how to deal with Diem emerged during the meeting, several concerns were raised regarding the United States' and especially the CIA's relationship with Nhu. The CIA had been having weekly meetings with Nhu, and one was upcoming. Since Lodge was opposed, it was agreed to cancel the meeting. US officials continued to disagree on the future of Nhu.

On the matter of replacing Richardson, McCone expressed his“unalterable opposition” to sending Lansdale as new chief of station (Document 5). McCone repeated his opposition one day later in a strongly worded and personal letter to Lodge.“General Lansdale,” McCone wrote,“would not be acceptable to the organization nor to me personally” (Document 6).[14]

The CIA's director was also very critical of Lodge's treatment of Richardson. Despite Lodge's claims that he had no problems with Richardson, intelligence collected by the Agency pointed to Lodge's efforts to ostracize Richardson. McCone did recognize, though, that Richardson was close to Nhu and believed that – were a coup to go ahead – he probably should be replaced (Document 6).[15]

Lucien Conein, CIA contract officer and main U.S. liaison with the coup-plotting generals.

In early October, the CIA's meetings with the generals restarted. By now, Conein had become the Agency's main point of contact with the Generals. Lodge, unlike Richardson, trusted him to execute his directives.[16]

In a meeting on the 2nd between General Minh and Conein, the former asked for a confirmation of US posture towards a coup and assurances that the US would not“thwart” a coup if one were to get underway. Minh stated that the Generals did not require US support and outlined three main options: i) the assassination of Ngo Dinh Nhu and Ngo Dinh Can, keeping Diem in office, ii) the encirclement of Saigon by various military units, or iii) a direct confrontation between the coup plotters and the remaining troops (Document 19).

On the 5th, Lodge asked State for confirmation of what Conein should tell the general the next time they met. Lodge agreed that the US should state that they would not thwart a coup; Conein should also offer to review the generals' plans, except for the assassination plans (Document 8).

On the same day, a telegram to Lodge confirmed US government policy.“No initiative should now be taken” the telegram read,“to give any active covert encouragement to a coup.” US officials should work to identify possible alternative leadership, but this effort had to be“secure and fully deniable,” as well as separated from the normal reporting work.[17]

Two days later, on October 7, the crippling dysfunction and mistrust between Richardson and Lodge became evident during a meeting among McCone, Colby and Richardson, who had been temporarily recalled to the US (Document 9).

Participants criticized the extensive compartmentalization of information and dysfunction in Saigon, with Lodge cutting the CIA country team out of the decision-making process. CIA leadership speculated that Lodge had used press leaks to further his position and undermine Richardson. The distrust between Lodge and the Agency had reached a boiling point.

The State Department was also on the case. It wrote Lodge that David Halberstam had a quote from him stating that he would have been happier with a new CIA station chief. State asked for the leaks to stop and to work together to“ensure a more accurate reflection of our common commitment to a single governmental policy.”[18]

The controversy surrounding assassination

As detailed above, the assassination of Diem and Nhu had been openly discussed by the generals with CIA operatives as an essential element to the planned August coup (Document 3). In October, when the assassination (of Nhu and Can) was listed as one of the Generals' preferred options, a controversy ensued as to what the US government posture should be.

With Richardson out, Acting CIA Saigon Chief of Station Dave Smith told Langley that he had discussed the latest Conein-Minh meeting with Lodge and his deputy William C. Trueheart. Smith recommended that“we do not set ourselves irrevocably against assassination plot, since the other two alternatives mean either a bloodbath in Saigon or a protracted struggle.”

Having received Smith's cable and perhaps already unwilling to discuss assassination with Lodge, McCone sent a stern reply (written by Colby) to withdraw Smith's recommendation since the US could“not be in a position of actively condoning such course of action and thereby engaging our responsibility therefore.” A CIA cable from Saigon confirmed that McCone's directive had been acted upon, and that Lodge shared the DCI's view (Document 19).

This exchange played a prominent role in the 1970s Congressional Investigations. Members of the Church Committee pointed out that McCone's directive – written by Colby – conformed with other last-minute telegrams that had been sent to distance the US government from any involvement in assassination.[19] A“CYA” effort in the words of one of the Senators.

During Colby's testimony, a key element of contention became whether Conein, the main contact with the generals, had been made aware of McCone's directive regarding assassination.[20] At the hearing, Colby had no specific answer. In a later correspondence between the CIA's William Elder and William Miller of the Senate Select Committee, the former had to admit that the cable traffic on the matter remained unclear (Document 21).

Toward the November coup

As General Minh's conspiracy against Diem picked up steam, the Executive Committee of the National Security Council (ExComm) held an off-the-record meeting on October 8 to discuss the South Vietnamese general's coup proposal.[21]

Although McCone and McNamara cautioned against Minh's plans, President Kennedy liked the proposal – given that it allowed the US to deny its involvement.“I don't know whether Big Minh's going to do it or not,” the President explained,“The only thing is, as I understand our position is, well, if he does it, all right, and if you don't do it, all right. We're not now – all this – the only difference is, we're not now going to him and asking him to do it.”[22] The coup was back on.

The CIA's Conein became the key liaison between the US government and the coup-plotting South Vietnamese generals. While CIA headquarters expressed some concerns regarding a possible set-up and an effort by General Tran Van Don to – at a minimum – entrap Conein, the meetings continued.[23]

In late October, Conein met Don at a dentist's office in Saigon to gauge Washington's appetite for a coup. Don told Conein that the generals were not ready to share the coup plan, but that he would receive it two days before the start of the coup. An agreement was reached that, when the coup began, Conein would be invited to the Joint General Staff (JGS) headquarters to secure a direct line of communication between the coup plotters and Ambassador Lodge.

Before a redacted section, the last available paragraph reads:“Without being questioned on this point, Gen. Don stated that Generals' Committee had come to the conclusion that the entire Ngo family had to be eliminated from the political scene in Vietnam”[24] A few days after the meeting, Lodge informed the Generals that Conein was authorized to speak for Lodge.[25]

On October 26, less than a week before the coup, several American officials began to get jittery over the conspiracy against Diem. In a message to National Security Adviser McGeorge Bundy, Lodge stated that he was unconvinced that a coup would take place, as he was not sure General Don had“the iron in his soul” (Document 10).

Lodge agreed with Bundy that a failed coup might have had negative repercussions for the US from“persons who wish to damage us.” Yet, if the US government played its cards correctly, Lodge still believed that the US would be able to maintain a“very vigorous denial” that it had played any role in the coup.

Three days before the coup, top US officials met at the White House again to discuss the prospects and consequences of overthrowing Diem, but they remained divided (Document 11). Chairman of the Joint Chiefs of Staff Maxwell Taylor stated that, regardless of the outcome, a coup would be“disastrous.” Building on Taylor, DCI McCone considered it unwise not to reconsider the US posture since the military adviser to the President (Taylor) was counseling against the overthrow of Diem and Nhu.

The President worried about the risk of protracted fighting. Robert F. Kennedy doubted whether the US should proceed with a plan that might either fail or create instability even in case of success, especially since a coup might undermine the war effort.

Bundy argued that the US could not reverse course and abandon the coup plotters.

The record of the meeting makes clear that Washington had widespread knowledge of a growing conspiracy against Diem. The meeting concluded with an agreement to send a cable for a new assessment of the coup's prospects (Document 11).

Four hours later, at another meeting in the White House, President Kennedy's doubts receded as he explained that“the burden of proof should be on the coup promoters to show that they can overthrow the Diem government and not create a situation in which there would be a draw.”[26] The President was clear: he wanted a successful coup.

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