"White nationalism" is basically an american phenomenon. English people aren't "white nationalists" they're English nationalists. Same with every other European nationalist movement. Same with Australia.

"White nationalism" is a result of the fact that, like black Americans, white Americans don't really belong to a historical nation anymore. So, they're present in north america as the white nation of north america. It's kind of an ethnic group at this point, a young one. The name of their nation is "white". That's the name of their ethnicity. They no longer control a state unilaterally, but a state is not a nation.