Now "she really is a force ... not in the sense of her marching into West Wing meetings .. but in terms of her monitoring the greater Obama mission," Kantor said. "There is a strong sense that the Obamas share a larger view of what they've accomplished. [My] book's last chapter is called 'What We Came Here to Do.' That sensibility still undergirds their time [in the White House]."

As she tracks Obama's evolution to this point, Kantor notes that the first lady's guardianship of her husband's image and espoused beliefs also imbue her with a certain caution. Kantor said that the first lady has not forgotten the mostly white backlash over the black nationalistic preaching of the Rev. Jeremiah Wright, the Obamas' former Chicago pastor. "It's interesting that the first lady has not had that kind of public gaffe [regarding] race," Kantor said. "But she will say things about race that are very clear ... That this problem of childhood obesity applies to everybody, but it disproportionately affects black and Latino families. Her statements on race are very understated and very clear."

An equally pivotal and positive moment in the first lady's own way forward, Kantor said, involved her 2009 visit to a London girls' school heavily populated by nonwhite, poor and immigrant students from asylum-seeking families.

"The way her advisers told me the story later [suggests] that this is when she really began to understand her potential first lady-hood," Kantor said. "The way they describe this ... She starts to choke up. It was almost like she could kind of see herself through their eyes ... She's talking to these girls about what they offer to society. She is hugging them; they are swooning. The Secret Service guys are getting nervous, but she keeps going and keeps going. She continued struggling for a while in the White House after that, but that moment kind of planted the seed for who she would become as first lady."

Katti Gray is a Brooklyn, N.Y.-based freelance writer.

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