What does the Constitution says about dual citizenship when electing our President???
Beside the point. No one has any proof that Obama has dual citizenship. Even if a child is granted secondary citizenship as a result of being born on foreign soil, that citizenship vanishes unless the individual actively claims that citizenship as an adult or has been living in that nation from childhood into adulthood. Not one shred of evidence that either of those criteria has been fulfilled.
I take it by your post, however, that you are now agreeing that Obama IS a natural born citizen of the U.S.