The many JFK conspiracists who say JFK was leaving Vietnam, pulling out after re-election (and that's why in part he was killed), repeatedly ignore the fact that the plan JFK supported was conditional, that the McNamara-Taylor report and proposal was a phased withdrawal contingent on the ability of the South to take on the war. That's not an opinion; it's in the documents. Doesn't matter how many times and ways one says this, they ignore it.
So what do they do when confronted by this? They simply make things up. About what NSAM 263 and what NSAM 273 said, about what the McNamara-Taylor report proposed and what JFK repeatedly said about the conflict. There's nothing in 273 that overturns 263. But they make things up and say it does. They never answer one obvious question: Why would JFK tell Hanoi that the US was unconditionally leaving in two years? That is, show his hand? In response, Hanoi would simply wait things out, wait for the US to leave and then resume its attacks. And force the US to return. Because JFK conspiracists are silly doesn't mean JFK was too.
Here is "Mr. X" in Oliver Stone's fantasy movie JFK: "Only four days after JFK was shot, Lyndon Johnson signed National Security Memo 273, which essentially reversed Kennedy's new withdrawal policy and gave the green light to the covert operations against North Vietnam that provoked the Gulf of Tonkin incident. In that document lay the Vietnam War."
That's not what 273 did. Once again, the conspiracy crowd is making things up or living in a fantasy world. Maybe both.
Here is NSAM 263:
https://irp.fas.org/offdocs/nsam-jfk/nsam-263.htmHere is NSAM 273:
https://irp.fas.org/offdocs/nsam-lbj/nsam-273.htmThere's nothing in 273 that undoes what 263 says.
As to Karnow: The man wasn't just a historian writing about events fifty years later. He was in Vietnam at the time of the Buddhist Crisis and Diem Coup and reporting on it. He knew what was happening, interviewed the people, reported on events, understood the history and culture. He saw firsthand the consequences of the government's crackdown on the Buddhists, how it was causing problems among the intellectuals, the students, and obviously the Buddhists. And that in turn was hurting the war cause, the defense of the South. How could it not? Moreover, it was causing problems for JFK as Congress and the public were souring on supporting the SV government.
Whether Diem *had* to crack down on the Buddhists to secure his political base, whether the uprising was caused by communist agents, is meaningless. The issue is the problems for the war that the crisis and Diem's response caused. None of that is debatable; they are facts.