That article establishes his liability on his mother's side. However, Comrade Obama probably is liable through his father's side as well. As the article points out, he is not an authentic American black, descended from slaves, but rather the son of an elite Kenyan tribesman whose ancestors were likely supplying slaves to the Dutch and Portuguese slave traders.
As a matter of fact, the Mooselimbs of Mauritania still hold slaves! What say you on that, Barack Hussein Obama?