[Secrets: A Memoir of Vietnam and the Pentagon Papers by Daniel Ellsberg, taught me that sometimes the truth is hidden in plain sight. In this case, all I had to do was open a book, and some of the truth spilled out. Bolded text is my emphasis.]
[Nguyen Cao Ky]
In the spring of 1966 there was another major Buddhist uprising in I Corps, the northernmost provinces of South Vietnam, including the cities of Hue and Da Nang. …
In the excitement of his strong U.S. backers, Ky decided to dispense with his greatest rival, General Nguyen Chanh Thi, perhaps the best military commander in ARVN. Though both Ky and Thi were Buddhists, Thi, who was in charge of I Corps near Da Nang, had closer relations to the Buddhists to the north. When Ky fired him, Thi refused to go and rallied the Buddhists to his support. They defied the administration in Saigon and joined forces with Thi, pressing for the replacement of the Ky regime by national elections.
At this point Lodge and MACV arrange to transport Vietnamese marines to Da Nang, along with tanks and air support, to put down the uprising. By this time monks, joined by women and children, had erected Buddhist altars in the streets and sat by them. The tanks of the ARVN First Division based in I Corps came up to the altars and stopped. They would not go through them. It appeared that ARVN tank crews were poised to join the Buddhist revolt. But on April 7, the day I was briefing the Mission Council, tanks transported by the United States from a different region rolled right through the altars. All the demonstrators, including the Buddhist monks, were arrested. Many Buddhists now went into the jungle to join the Vietcong, while others were arrested and tortured.
[Gen. Nguyen Chanh Thi]