Final answer:
Federal policies in the 20th century sought to reduce disparities but met with mixed success. The GI Bill often failed to benefit all races equally and the retreat of affirmative action policies in the 1980s widened the gap. However, civil rights advances did lead to an increase in the black middle class and a challenging of past simplistic historical narratives.
Step-by-step explanation:
Federal policies during the middle decades of the 20th century attempted to narrow class, race, and ethno-religious differences, but were met with varied outcomes that often depended on complex social, political, economic, and cultural factors. One of the key factors that influenced the increasingly wide gap between white, middle-class Americans and those living in the 'other America' was the GI Bill of Rights, which provided education and housing benefits to returning World War II veterans but was not equally accessible to all races, particularly black Americans.
Following this, the civil rights movement and associated policies like affirmative action played significant roles in helping some black Americans join the ranks of the middle class, while others remained in poverty due to overarching issues like ghettoization, job loss, and reduced federal support for community programs. Despite these efforts, the retreat in support for affirmative action during the 1980s, and the introduction of societal ills such as crack cocaine, further exacerbated disparities within urban black communities.
Historians have also begun examining the complexity of black history, showing a rise in black education and entrepreneurship alongside increased racial violence during the early 20th century. This new perspective brings to light the fact that there was not a monolithic African American experience or response to oppression, as evidenced by the numerous and varied civil rights cases during that era.