Let me clarify. I likened fighting to holding noncompromising stances and declaring extremely harsh criticism against progressivism. Nobody has truly fought with force against the leftist march through the institutions. But let me list some names that Buckley black listed over the years for being right wing radicals. Paul Gottfried. Sam Francis. James Burnham. Murray Rothbard. Clyde Wilson. The John Birch Society. Peter Brimelow. Joe Sobran. John Derbershire. All but two of those were off the top of my head.
You may disagree with these guys or at least part of what they taught. I do too. But they were all voices on the right that were much more radical and were pushing for much more uncompromising policies to protect American culture and the American constitutional order.
I'm not aware of them going after Burnham. Everything see from NR on him is positive. As for the others, they weren't criticized for being uncompromising. They were criticized for substantive differences. Most of them were either libertarian-types, and some were white nationalists. Yes, I know the Left says everybody to the Right of Mao is a white nationalist, but a few actually are. Hell, Brimelow went to work for Richard Spencer's website. I think we can fairly call him a white nationalist who shouldn't be associated with mainstream conservatism.
And some were just an embarrassment like JBS accusing Eisenhower of being a communist agent as well as the Dulles brothers and George Marshall. To make that kind of accusation, you need compelling evidence. He didn't have it but crusaded on that nonsense anyway, and it was hurting conservatism's credibility. Buckley cared about that, and he was right to.