I don't mean to nitpick, Tom, but is this really your plan?

I'm not sure I'd go that far -- it was more that certain people could be declared outside the black community; there was no reason to think that the white community would consider them members. But there was definitely the idea that blackness (like many feminist theorists say about femininity) was something to construct and achieve -- except one has to do it naturally, authentically, and can't ever be seen to work at it. Whites could be inauthentic if they pretended to be black, but otherwise whiteness was just automatic.