Gen. Duong Van Minh Warned US That Diem Was a Puppet of His Brother

By Desmond Okafor · August 18, 2026

South Vietnamese generals plotted to overthrow Ngô Đình Diệm while treating US demands for reform as a joke. This Secret memorandum remained hidden in National Security Files for decades.

The officers of the South Vietnamese army spent 1961 measuring the distance between their president's promises and the reality of his family's grip on power. They viewed the official reorganizations of the state not as progress, but as a performance designed to keep American dollars flowing while the country burned.

A memorandum dated November 28, 1961, written by Roger Hilsman, the Director of Intelligence and Research, and addressed to the Secretary of State, captures a government in the early stages of a collapse. Hilsman reports that "top south Vietnamese military leaders may be plotting a coup" against President Ngô Đình Diệm. This was not a sudden tremor, but the result of a deepening rift between a dynastic executive and the men tasked with fighting the war.

"Shams" to Fool the Americans

By late November 1961, the facade of cooperation between the Diệm regime and the United States was cracking. Maj. Gen. Duong Van Minh, the Commanding General of the Army Field Command, didn't mince words when speaking to the US Army Attaché on November 24. He described Diệm’s attempts to reorganize the military establishment as "shams" intended to deceive Washington.

Minh's frustration was not merely administrative; it was existential. He expressed "acute concern" over how Diệm and his family interfered in military operations, signaling that the chain of command had been replaced by familial whim. According to the memorandum, Minh warned that the situation was "extremely grave" and that the coming months would be decisive. He was not alone in this assessment; Brig. Gen. Le Van Kim, a known critic of Diệm, was present for these remarks and "obviously agreed."

December 1

While General Minh provided the strategic critique, others were discussing the calendar. Col. Pham Van Dong, Deputy Commander of the 3rd Army Corps, told the US Army Attaché that he had been weighing "coup possibilities" with Brig. Gen. Le Van Nghiem. While Nghiem remained cautious, stating he would "wait and see how things go before we take sides," Dong was far more urgent.

Dong told the Attaché that "something must and will be done very soon, possibly by December 1." This specific date underscores the volatility of the period. The plotters were not just waiting for a political shift; they were timing a strike.

The Puppet and the Brother

Central to the military's disgust was the shadow cast by Ngô Đình Nhu, Diệm’s brother and political adviser, and the influence of Madam Nhu. In the eyes of the generals, the President had ceased to be an independent leader. General Minh told American officials that he considered Diệm to be a "puppet of Nhu."

Col. Dong went further, suggesting that Nhu was not merely influencing his brother but had his own independent "plans for taking control of the government." The memorandum notes that even those who nominally supported Diệm blamed Nhu for the anti-US press campaigns appearing in Saigon. The brother was the lightning rod, the perceived architect of a regime that was becoming increasingly alienated from both its own army and its foreign patrons.

A Signal From Washington

The memorandum reveals that the plotters were not acting in a vacuum. They were watching the United States to see if the support for Diệm was finally evaporating. Hilsman notes that military and civilian leaders, including Vu Van Thai, a former Director General of the Budget and Foreign Aid, had urged the US to take a "firm stand" with Diệm.

The generals believed the anti-US rhetoric in the Saigon press might have weakened Washington's resolve. Hilsman warns that the plotters' estimate of US intentions "could strongly influence a decision to undertake a coup." Essentially, the generals were checking the wind to see if the Americans would provide the cover—or the encouragement—necessary to move against the palace.

This Secret memorandum was later attached to a transmittal for McGeorge Bundy and was seen by Gen. Maxwell Taylor. While the December 1 deadline mentioned by Col. Dong did not trigger a regime change in 1961, the pattern was set. The public record shows that on November 1, 1963—nearly two years after Hilsman's note—CIA-backed officers finally carried out the coup that deposed and killed Ngô Đình Diệm and his brother.