Otherwise known as Nazism: The concept of Nationalism taken to its extreme in an era when Communism and Socialism were gaining broad support among the poor. In the nation of Germany, National Socialists blamed the tiny minority of non-natives for all crises, depressions and military losses. They used the "Socialist" moniker to draw in popular support.
National Socialism, by that name, no longer exists.
The National Socialist German Workers party promoted itself using "The Big Lie": a blatant lie about its opponents, told often enough, assumed to be true. The Big Lie (the ideology itself) was promoted by the party's propaganda wing. By assuming control of the church, scouting organizations, schools and universities, the Nazi party was able to gain broad support. No one wanted to be unpatriotic after WWI, and thus criticism was easily stifled.
Protests were astroturfed to build hatred against Jews, Socialists, Communists, gays, and intellectuals. The Center Party liked the Nazis' anti-Communist, free market beliefs and allowed its rise to power in what was probably the worst political underestimation in history. The Nazis then banned the Center Party.
National Socialism is neither: It seeks to divide people up to more easily conquer them according to their hatreds. It also goes directly against the ideology of Socialism because it teaches people to identify with their race, not their social class.
In a country like the United States, for example, a future takeover by ethnocentric fascists with brutal ends would, once again, assume a false identity - probably something like "Pro-American Christian Party" - then proceed to wrap itself in the American flag (or a similar, less well known patriotic symbol, like the Gadsden flag), go to church to get schooled on religion (and to disguise any anti-Christian motivations, such as Ayn Rand's Objectivism), pretend not to be racist, then promote itself as the only hope for the future.
Oh, wait ... that already happened. Shit!