Well look at that, my second year course was on the American dream between 1940 and 1980. I am not sure how you have been told to structure your coursework but we were told to choose three points. Firstly, i would compile evidence for the presidents' actions (look at legislation passed such as the Civil Rights Act 1964) as well as things such as JFK's open support of Martin Luther King (JFK called MLK's wife and reassured her he would support his release from prison). My second point would be about the protests of African American people, such as groups like CORE, SNCC, SCLC as well as actual protests. I cannot remember which group but one appealed the decision in Brown V Board of Education in the supreme court and won (I believe it was about segregation in schools and not sharing books between different schools). You could counter this point by saying that in the deep South, African American's were not as willing to protest as the Jim Crow laws were still in place and justice was rarely served for those who suffered violence and Lynching's (you could write about the murders of the Freedom Riders).
I have not done pre-1940's America and so couldn't accurately help you out there at this point in time.
Have you been given instructions on how to structure your coursework? I still have access to what I was given if you need it as well as America resources.