When my maternal grandparents (and as many of their relatives who could scrape together the money for a steerage-class ticket) showed up in America in the 1910s from god-forsaken southern Italy (a very distinct place than practically Austrian/French/Swiss and hence semi-legitimate northern Italy), they weren't white. No, they and their dusky skin, short bodies, and (obvious!) lack of intellectual capacity and impulse control were a big part of The Passing of the Great Race, or the pollution of the Nordic blood that defined true Americans, in Madison Grant's influential, idiotic thought. One of the great achievements of the 20th century (for my family, at least) was that my parents, born of Italian parents on side and Irish immigrants on the other, emerged as fully white and American within 40 or 50 years of being born. It only took suffering through the Depression, really, and supplying infantry members in World War II and Korea....
What counts as "white" has always been fluid and fraudulent, but it often (always?) comes at the expense of some new out-group.
Me: I recently wrote about the genetic history of how light skin became common in Europe in the first place; in short, the key genes spread through mating with dark-skinned people. That fact alone shows the absurdity of the alt-right Weltanschauung (that's German, by the way, for the benefit of today's defenders of European heritage). But all this only hints at the problems the alt-rightists will have in trying to build a movement (let alone a country) that's all-white and only-white. Look at the item below, now circulating on white nationalist twitter. I for one question how well the "Spanish" guy in row 2 is going to fare in a strictly "white" vanguard, and I have doubts about the "Italian" and "French" guys as well, leaving aside the absurd stereotypical additions to the latter.
On the other hand, maybe that idiotic tweet is more open-minded than a lot of alt-right thinking, which tends to implicitly exclude self-described white Hispanics as being white. (If you were to include them in projections, the supposed problem of U.S. whites declining from majority into mere plurality looks likely to never even occur: click to enlarge table.)#WeStandWithYou against multiculturalism and the dispossession of White people in their own country. #AltRight pic.twitter.com/2JWhpIvnIz— Owen McCormick (@Mac_Tire_) September 17, 2016
So much for "white genocide." And here's a bit of history from a previous time a group of people thought they could defend the "Western world" while dropping such Western values as pluralism and democracy. It's about the Battle of Stalingrad, from The Rise and Fall of the Third Reich (click to enlarge):