How can discrimination affect nationalism or patriotic beliefs?

A lot of nationalism, or very strong patriotic beliefs, is based on the idea that an individual's nation, region, belief system, or group is the very best, which would mean that all other nations are inferior. This belief allows for the beginnings of discriminatory feelings towards those who are members of inferior groups. Over time, and through radicalizations of nationalistic ideology, discrimination becomes commonplace for many, even going so far as to be directed towards descendants of inferior individuals who are in fact themselves members of the "very best" with no connections other than ancestry to any other group.