For the most part, whites did NOT have slaves, in what is now Zimbabwe and the RSA; but the BLACKS did; primarily the Zulus!
There aren't as many blacks, mulattos, Indians of various types, Asians, all put together, here, to out number whites, in the same proportion as in RSA, when Apartheid ended.
The crazed Muslims, here, will "get us", long before the blacks or STUPID Mexicans shall.
We already have a quota system for the police, but black cops, here, still do the job; unlike what goes on in the RSA!
Compare this nation with Venezuela...if you REALLY want to see what we'll be like, if Hillary gets elected somehow; or Bernie.
You forget the number one problem AND the only thing keeping the whites from prevailing in SA--despite their being only about 5% of the population--the traitors of their own tribe in their midst and globally.
And THAT is the biggest threat we face.
But the comparisons to Brazil alone are not apt.
Brazil has one language and, mostly, one religion.
Also there is not as much anti-White hatred/ guilt. Many mestizos and mulattoes consider themselves white; white is often considered desirable, attractive etc.
Even if the entire white population mixes away (not that it would be a good thing), Brazilians are not as hateful against themselves as whites are(removing flags, destroying monuments, offending ancestors, denying religion, etc).
Again, with combined forces of a self hating white population and the white hating others--racism against whites will be institutionalized ala SA to pay for all our transgressions: slavery, white male patriarchy, colonialism---unless of course there is a massive unforeseen change and quickly.