During his visit to Ghana, President Barack Obama laid out a U.S. policy that wasn’t any different from that of his predecessors. But because Obama’s father hailed from my home country of Kenya, and because blood –- African blood, especially -– is thicker than water, Africans exempted their son’s plan for the continent from the tough questions it warranted. To understand how important blood lines are in Africa, we have to go back to May, when Obama announced his plans to visit Ghana. Euphoria gripped the continent so tightly that instead of talking about what kind of relationship Africa should...