“The reason why I said yes was because I am tired of being afraid,” Michelle Obama told a crowd in Council Bluffs, Iowa, during the State Fair, in August of 2007, explaining why she had signed on to a long-shot campaign to elect her husband, Barack Obama, President of the United States. She stood in a middle-school gym, surrounded by a mostly white audience that was only beginning to know her husband and had an even vaguer idea of who she was. The stage was a small, low platform, but Obama, dressed in black pants and T-shirt, with her hair pulled back in a bun, occupied it like a dancer, punctuating her seven-minute address with appealing turns and pauses, as her listeners responded. The decision to run, she said, had…