Obama works out like “a gladiator,” a friend has said. When people—they’re almost always shorter—ask her to pose for pictures, instead of bending her knees she leans at the waist, like the Tin Man. Her winningly chipmunk-cheeked smile is doled out sparingly, a privilege to be earned, rather than an icebreaker or an entreaty. Obama, who graduated from Princeton, earned a law degree from Harvard, and became, first, a corporate lawyer and, more recently, the vice-president for community and external affairs at the University of Chicago Hospitals, spent all but the first year of her childhood in a four-room bungalow on Chicago’s South Side. Having traversed vast landscapes of race and class, often as a solo traveller, she evinces the discipline and, occasionally, the detachment of an Army brat.