Barack Obama receives the award as a recognition of potential, of which some has already been realized. It is not unprecedented, but it is not usual. I don’t doubt that Barack Obama would like a Nobel Peace Prize, but being the person that he is, I highly suspect that he would have enjoyed one awarded on the basis of acheived results rather than potential much more.
Jesper defending that Obama deserved to be nominated, but not the winner. I agree with him, and I think Nobel prizes shouldn’t be given for the potential, but for the achieved results.