USA and white - "Cracker" and "Nigger" aren't even comparable. As someone said, no white person was ever lynched by a mob with no legal consequence. No white person was ever stolen from his land and put into slavery with the at least tacit acceptance by the entire "civilized" world.
But history is history, and we ignore it at our peril. We should hear the words, and be uncomfortable saying them, and accept that our history is full of uncomfortable truths. I find it fascinating and uncomfortable that the black community has accepted the use of the N word internally, but I also understand it - to claim a word is to deprive it of it's power over you. This is the same reason that the gay community has adopted "queer". There is no equivalent for straight white people simply because we've been in charge for so long.
So I'm aware, and I would never use the N word, or any word used to persecute a minority, in any conversation, although I'll include it in a quote - but I'll be VERY aware of my audience, and I'll probably even say "This quote contains language that I find offensive". Which is all very interesting, because I don't really consider myself very Politically Correct, it's just my nature to avoid insulting words of any kind.
My father published a book of his essays recently. He was very conflicted about whether to include an essay describing his High School's minstrel show, and his reaction to it, because he was embarrassed that he had even taken part in it. However, I pointed out that his teacher had allowed him to take the only non-blackface part because he had expressed his reservations, and it's a little much to expect a 15-year-old kid in 1950 to take a stand against his teachers and refuse to take part. So he kept it in, because it's a part of history and the story should be told, and understood.