What notion does Kennedy seek to reinvent in this passage? Why is it necessary for this notion to change? What long-term result does Kennedy expect to see through the reinventing of this notion?

Question

anonymous · Answer

"One hundred years of delay have passed since President Lincoln freed the slaves, yet their heirs, their grandsons, are not fully free. They are not yet freed from the bonds of injustice. They are not yet freed from social and economic oppression. And this Nation, for all its hopes and all its boasts, will not be fully free until all its citizens are free. 

We preach freedom around the world, and we mean it, and we cherish our freedom here at home, but are we to say to the world, and much more importantly, to each other that this is the land of the free except for the Negroes; that we have no second-class citizens except Negroes; that we have no class or caste system, no ghettoes, no master race except with respect to Negroes?"