Why does lee write a letter to his son?

Lee writes a letter to his son to develop his thoughts on the prospect of the future of the Union. He discussed his feeling torn regarding whether to support the South in secession or the Union, and the fact that he regrets that the choice will likely exist to begin with. 

The  civil rights act of 1964, which ended segregation in public places and banned employment discrimination on the basis of race, color, religion, sex or national origin, is considered one of the crowning legislative achievements of the  civil rightsmovement.