Is it correct to classify Obama as the first black president"

[kılıç_mehmet]

Well, technically, for the longest time in America, if a person had any black ancestry, even if they looked white, they were considered black.

This makes little sense to me, but well...

For what it's worth, over 58% of Black americans have as much (or more) white ancestry as Homer Plessy had black ancestry.

Is it traceable? Well, not that it matters anymore, since from what I understand, the afro-americans now have their own communities and are a minority of their own right.
Most of them would probably not boast any heritage besides the ones they're aware of. However, Obama is quite aware that his mother is white*.