[Glenn]

If you didn’t know a thing about Obama and saw him on the street, how would you describe him?

He’s black.

[aruanan]

If you didn’t know a thing about Obama and saw him on the street, how would you describe him?

He’s black.

Only because you're so used to seeing mixed race folks who are called black. Take him over to Sudan (or many other places in Africa or in comparison with his own dad) and look at him and you'll say "mostly white".