Part 2 here and Part 3 here.
In 2008, William Buckley recalled the 1962 National Review article that effectively excommunicated the JBS from the conservative movement:
Unless Welch himself disowned his operative fallacy, National Review would oppose any support for the society.
“How would you define the Birch fallacy?” Jay Hall asked.
“The fallacy,” I said, “is the assumption that you can infer subjective intention from objective consequence: we lost China to the Communists, therefore the President of the United States and the Secretary of State wished China to go to the Communists.”
“I like that,” Goldwater said.
What would Russell Kirk do? He was straightforward. “Me? I’ll just say, if anybody gets around to asking me, that the guy is loony and should be put away.”
“Put away in Alaska?” I asked, mock-seriously. The wisecrack traced to Robert Welch’s expressed conviction, a year or so earlier, that the state of Alaska was being prepared to house anyone who doubted his doctrine that fluoridated water was a Communist-backed plot to weaken the minds of the American public.
In the next issue of my magazine, National Review, I published a 5,000-word excoriation of Welch:How can the John Birch Society be an effective political instrument while it is led by a man whose views on current affairs are, at so many critical points . . . so far removed from common sense? That dilemma weighs on conservatives across America. . . . The underlying problem is whether conservatives can continue to acquiesce quietly in a rendition of the causes of the decline of the Republic and the entire Western world which is false, and, besides that, crucially different in practical emphasis from their own.