Most aspiring presidents and prime ministers face a myriad of challenges as they embark on their journey. Controversial issues, questions about ethics or past conduct, wounds within their party all raise their heads. But the doubts that Barack Obama faces are far more existential than the superficial questions about most candidates. They go to his very core as a person, calling into question his values, his world view, even his patriotism. Hard racial divisions have softened in America, but fear of the “other” persists. Their possible next president has a strange name. He grew up in Hawaii and Indonesia. He...