(fascism) a governmental system led by a dictator having complete power, forcibly suppressing opposition and criticism, regimenting all industry, commerce, etc., and emphasizing an aggressive nationalism and often racism.
http://www.dictionary.com/browse/fascism
I don't know that much about them, but I think White Nationalists in the US want the nationalism and racism without the authoritarianism, but I could be wrong. I honestly don't think they've given it that much thought. The closest I believe any of those type groups have gotten to actual Nazis is when David Duke ran for office. Their primary objective seems to be "spreading the word." That's one of the reasons I don't like comparing them to Nazis. The Nazis were much more organized, intelligent and dangerous.