As Auma said to me: “He was trying to figure out who he was. He needed to be whole to be able to do what he’s doing now. He went about it the right way. A big chunk of his life was missing. It’s very healthy that he now knows he has these roots here.”

Image Roger Cohen

Those roots were discovered during Obama’s first visit to Kenya two decades ago. During that trip, as recounted in his memoir, he encountered Ruth in Nairobi. She is described as “a white woman with a long jaw and graying hair.”

But who is Ruth, a woman who divorced Obama’s father, remarried, and gave the family name of her second husband to her two sons by Obama Sr.? In the book she says, with less than exquisite tact, to Barack Obama: “But your mother remarried. I wonder why she had you keep your name?”

As for Ruth’s son, and Obama’s half brother, Mark, the one in China, he’s described as studying physics at Stanford in the 1980s. “The things Mark studies are so complicated only a handful of people really understand it at all,” Ruth enthuses.

But Mark, “a black man of my height and complexion,” tells Obama his work’s a breeze. He expresses limited interest in their shared father who died in 1982 at 46: “Life’s hard enough without all the excess baggage,” he muses.

If nominated, Obama’s family baggage will get pored over. Four years ago, Bush’s people cast Kerry as un-American for speaking French. A Republican camp campaigning at the sorry nadir of Bush’s handiwork will try to portray the war hero John McCain as more American and patriotic than his opponent.

But things are different. Less fearful, Americans are less willing to be manipulated. They’ve backed Obama this far in part because they’re sick of the narrow American exceptionalism of Bush’s divisive rule.