If Barack Obama wins the presidential election tomorrow, the world will doubtless marvel at the racial threshold the US has crossed. Perhaps even more striking, however, will be the prospect of the country's first black first lady moving into the White House with her two young daughters.

Often compared to Jacqueline Kennedy, who also raised a young family in the White House, Michelle Obama has evolved into one of her husband's most effective advocates. Her every outfit scrutinised and her every sentence minutely parsed, she has withstood a searing media focus over the past 21 months.