Hi, I'm going to answer this with some of my general knowledge.
During the time of the World War and after, there was a lot of resentment of the government by the American people. They felt that our government was <u>too concerned with foreign affairs</u> when there were so many domestic problems happening at home: racism, sexism, homophobia etc.
Also, after the War, the<u> economy was booming</u> and healthy. More African-Americans were <u>apart of the middle class and stable</u> enough to concern themselves with the Civil Rights Movement.
One other thing is the rise of Civil Rights Activists like Martin Luther King or Malcolm X or groups like The Black Panthers at the time.
This helped propel the Civil Rights agenda.