How did african americans challenge segregation after world war 2

When African Americans fought in WWII they were treated by the French (and others as well) with respect and did not feel as though they were being segregated. Therefore when they came back to the states they was a rise in militancy from the African American veterans. Although during the 1940's the United States was occupied with the Cold War it was not until 1955 that the civil right movement had began, leading to African American's challenging the court with issues such as Brown vs. Board of education in 1954. The movement as whole involved non-violent protests. 

Independent executive agencies are more specialised.