Who counts as a white nationalist?

I don’t do Twitter, in part because it’s a medium that lends itself to plenty of misinterpretation and willful misunderstanding, but what the heck is this?

Matthew Yglesias@mattyglesiasI It’s been fairly common over the past 5 years for people on the left to describe people (Tucker Carlson, Steven Miller, whoever) as “white nationalist” as a way of making a rhetorical point — linking folks they disagree with to more extreme forms of ideas they see as similar.4:20 PM · Jun 25, 2021 from Elkton, MD·Twitter for iPhone

What is the claim here? That Tucker Carlson and Steven Miller aren’t “really” white nationalists? Under what possible definition of white nationalism would Carlson and Miller not qualify as supporters of that ideology? The only one that I can think of is something like, if you’re a top White House advisor or the host of the most-watched cable news show in America, you can’t really be a white nationalist, because white nationalism is a fringe position in American politics.

This is an argument that would have made a certain amount of sense, oh, I don’t know, 20 or 15 or if you’re feeling super generous ten years ago, but in 2021? Is Yglesias turning into David Broder with a more demographically interesting name?