Right wing white supremacist terrorism is clearly international. The New Zealand shooter's manifesto contains the same grievance and fear of invasion and replacement of white people expressed by Anders Breivik, and the Squirrel Hill shooter. The POTUS likewise uses the same invader grievance, playing down right wing white supremacist terrorism saying it's a "small number of people" when asked if it's a growing problem, even though FBI considers it a growing problem and has for over a decade; while in the same statement repeats his hyping of problems on the southern border, calling it an invasion, despite ~40 year low in southern border interdiction and crime including illegal border crossing. The invader grievance by POTUS is not lost on people who study white supremacy in the U.S., nor is it lost on actual white supremacists. Nor was his entire five year racist lie of birtherism. Simultaneously with his rants about violence committed by Muslims, POTUS cut Countering Violent Extremism funds which focused on mitigation of white supremacists and neo-Nazis by de-radicalization therapy.

So the right wing white supremacist problem, at least in the U.S., has been taken seriously; but with political change it has been taken less seriously by the current administration, for entirely predictable reasons. Whether FBI takes it seriously enough is an open question, but when intelligence agencies publicly list threats to the U.S., the southern border is not on the list, but right wing white supremacist hate groups are.

There is a very real issue that until there is planning or solicitation to commit violence, right wing white supremacy is legal freedom of association, and hate speech is still protected speech, so long as it's not in the gray area of "fighting words". I think it's completely reasonable for FBI to infiltrate violence prone hate groups by paying informants and putting agents on the inside. I also have no problem with enduring warrants on leader organizers of such individuals for wire tapping. What they want is a race war. They want to destabilize the country. It's not a new thing.

ADL and Southern Poverty Law Center have been tracking hate groups for a long time, both left wing and right wing. It just so happens right now it's overwhelmingly right wing hate groups out there. And it would not surprise me if the more violent prone ones would love to see successful recruitment of left wing groups, because they can't really have a race war, or make real their romantic notions of a civil war 2.0, with just a bunch of right wing groups. They have to incite the left to attack, or they've got nothing.