I guess America has failed its mission as a melting pot actually. Recent burst of violence in Ferguson and other American cities only proves the fact.
I've got many friends among USA citizens, some of them Afro-Americans. I should say they are all not quite satisfied with their life in the USA. White Americans are annoyed with the necessity to have number of Afros in their relevant companies in the same proportion as the concrete state has them. They say it has nothing to do with some race likes or dislikes. It's life observation just that Afros in most cases are worse educated and less gifted. They also often have attitude problems.
As for my Afro-American friends they are absolutely sure that the WASPs are prejudiced toward them and they actually hate the idea that any Afro can take off, leaving them behind. In a word, it's actually long-standing huge stress which spilled out to the streets in Ferguson and other places.
I tend to think it's alarming, for it may be start of some revo or sort of it to improve things in the USA, to make it healthier economically and politically.