So you think segregation is a thing of the past? Apartheid was just in South Africa? Well... have a look at North Carolina's 12 district. Not only does it carve red from blue, and haves from have-nots; it separates regions by melanin...
Many state legislatures have attempted to racially gerrymander their district boundaries; recent examples include AL, LA, NC, and VA. Fortunately, these tortuous district perimeters can be challenged in the courts, and there they have been consistently failing.
In 2012 Alabama's Republican legislature's instituted racially gerrymandered district boundaries. The Alabama proposal was struck down by the U.S. Supreme Court.... this past March... 2015! Yes, it took several *years* of legal battles to reach that point, and by then, considerable damage was done.
The Republican Virginia legislature's racial gerrymandering around Richmond was just struck down a few days ago- a significant victory. But wait: a similar plan was struck down last year, so this is an ongoing battle and there is no solution in sight. Voters would likely need to elect new Delegates to break the impasse.
It is important to note that Democrats have pushed for racial gerrymandering as well. The implied liberal argument for it (which sounds fair at first) is that minorities would not be adequately represented without their own districts. And so there are some representatives who wouldn't possibly rise to office without some special assistance. This is an insidious practice which grooms leaders who represent the white people or the African American people, but seldom serve the People as a whole. And then we wonder why we feel divided...
The implied Republican argument for racial gerrymandering, I suppose, is that African Americans will always vote for their own. This is a self-fulfilling prophesy: if you don't work, year after year, to represent everyone, transparently, then the population will naturally self-segregate.
The lesson from South Africa and perhaps also Israel is that once you lock in geographical boundaries -whether by fence or by district boundary- racial tensions increase. People get a sense of "us" versus "them;" they notice more crime there than here; they notice more prosperity here than there, etc. After a generation or two, there is Apartheid-in-effect.
And that is toxic to American democracy.