What was the most important issue that led to the emergence of the civil rights movement in the South and Southwest?

The most important issue that led to the emergence of The American Civil Rights movement in Southern states was social discrimination towards African Americans and segregation by race of public facilities especially in Southern states (which in previous years fought to keep slavery legal and wanted to secure a cheap workforce).

The Civil Rights Movement were social protests during the mid 1950s and 1960s that wanted to end social discrimination and racial segregation against African Americans and secure federal protection to their rights stated in the Constitution.

There were two events that marked the beginning of the Civil Rights movement, the case of Brown v. Board of Education in 1954 that changed the Supreme Court's decision towards racial segregation (racial segregation before this case was allowed as long as conditions were equal) and the arrest of Rosa Park when she refused to give up her seat to a white passenger.