Most racially mixed people consider themselves non-white and vote accordingly. Many of the most lunatic black nationalists are half white.
A lot of the rebel Indian chiefs who fought the US Cavalry were half (or more) white. Call it hybrid vigor. Call it superior smarts inherited from their white forebears. They were Indian enough to be leaders of the Indian community, but also had the superior raw intelligence (IQ) necessary to beat out most of the full-blooded Indians competing for leadership positions. There's this fortune cookie saying "It is better to be the head of chicken than the rear end of an ox". That's why Obama sided with his black half. And he was lucky in that choice - it ultimately took him all the way to the White House.