Jim Crow laws started around the end of the reconstructive area in the late 1870s to early 1880s. Jim Crow laws separated African Americans in the south to stop using the same Water fountains stop going to the same Theaters and restaurants as the whites living in the south. Jim Crow laws ended in the early 1950s.
The next big thing for bringing down segregation was the signing of the civil rights act in 1964. This happened after The March on Washington when Dr. Martin Luther King Jr. marched with a group of Blacks and Whites marched from Mobile Alabama, and it was a 5 day 54 mile walk. It was this when Martin Luther King delivered his famous I Have A Dream Speech. After that Lyndon B Johnson signed the act into law.
The Non Discrimination Policy was signed into law in the early 1900s. It was used to protect the African Americans from things like unlawful killing. But over the years and it kinda fell out so in Bill Clinton's run as president he resigned it into laws and it does not just help minorities but it helps the LGBT-Q community in the workplace.