I have a very smart Asian supervisor who knows the department very well but he wasn't chosen to be the manager of it and instead they put a black manager in the position who knows nothing compared to the Asian man. It's not just whites that get discriminated against, although they're often put at the bottom of the barrel for promotions and hiring.
I also had a Mexican supervisor at my last job who got passed over for a promotion that she deserved and worked hard for. Again it was given to a black.