While segregated and limited largely to non combat roles, about one million served in the u. s. military during the war?

The correct answer is the "African Americans".

Before, African American served as slaves to different people, they were believed to be of lower racial rankings, which is why they are forced to be slaves. During the times of their persecution, they served as free individuals and slaves as well. They also fought in different wars, though they are segregated from the White-Americans and persecuted.