Are you asking for some examples of challenging the color barriers? if so then some examples are the Little Rock Nine trying to desegregate schools, and the Greensboro Four who sat at a counter in a diner marked only for whites and they were harassed but they were always polite.
Because the cause/s of war is/are controversy in beliefs. Also because they believed they had a right to do what they wan to do and the north had no reason to get in it.
