Beginning about 1980, approximately twenty states enact segregation laws

The effect that it had includes:
They enforced compulsory segregation of people along racial lines so African Americans couldn't swim in the same swimming pools as whites.

People of Native American descent were denied a public education and in many cases forced to attend boarding schools to wipe out any trace of Native American heritage.

It resulted in the "separate but equal" policy that was eventually ruled unconstitutional.