Nowadays, you are a racist if you simply believe that your own race should continue to exist. For example: Where do white people come from? Answer: two white parents.
The definition of “white” is tricky when most have some mixing of blood. An Arab is classified “white”. Plus, plenty of Americans have Indian blood.
Race itself is a dying / weakly defined categorisation.
It’s unlikely that all the US will interbreed into one light tan race. But if they do, so what; they would still all be children of Adam (and Noah). It isn’t the skin that matters, it is what resides within the skin that matters.
being bi-racial is kind of in these days due to Obama.