The term Race war is a slang term, referring to develping hostilities between ethnic groups divided on the basis of race.
Since race is a superficial distinction, the term 'race war' is generally used by people for whom the superficial nature of skin color bears significant symbolic value. The term may refer to specific violent acts or to general overt or covert hostilities between ethic groups.
The concept of a 'race war' is a core rallying cry for racist extremist groups. In general, their members claim a understanding of religious scripture of a deeper level than others have. They also make direct or symbolic associations between elements in religious scripture and elements in human cultures present today with the added aspect of advocating a survivalist agenda, separated by racial identity. In 1987, the White Patriot Party declared that a Race War had begun. Some white supremacist groups advocate a Racial Holy War.
A sophisticated understanding of race and racism establishes these as different incarnations of cultural warfare human exploitation, and in its modern form, racism is a blending of long standing ethnic conflicts, and a western quasi-scientific rationalisation for abuses such conflicts may bring.
When Charles Darwin formulated his Origin of Species, he could not have forseen, that though it would find disfavor as a contradiction of religious scripture, it would also be perverted in the minds of some as basis for eugenics, or agendas supporting ethnic superiority.
The Nazis made claims of an existing long-term covert race war instigated by the Jews against "Aryans" European cultures, and this became, in part, political justification to begin a campaign of overt anti-Jewish operations, leading to genocide.