First Ladies of fashion are outsmarted by latest model

On a brand new page on the official White House website, the new First Lady is introduced to her public. "When people ask Michelle Obama to describe herself, she doesn't hesitate," it reads. "First and foremost, she is Malia and Sasha's mom."

At the inauguration of her husband on Tuesday, Mrs Obama had to be more things to more people than just a mom. As a metaphor for her husband's presidency, she had to represent change, hope, loyalty, feminism, charm, intelligence, and an end to the recession. And all she had to do this with was two frocks. Luckily, this is not a woman to shirk a challenge.

For the swearing-in parade, her look was perfect. The choice of Cuban-American designer Isabel Toledo represented the openness of the new administration's foreign policy. The colour ("lemongrass") symbolised hope and freshness. Most of all, the ensemble said: I am so attractive I can still look good in acid yellow. It was the frock of an icon.

If the daywear was a success, however, the ballgown was a triumph. A nation sighed as the President introduced her: "First of all, how good-looking is my wife?" In an ivory silk chiffon gown by Jason Wu with organza flowers and Swarovski crystal rhinestones , she took on Jacqueline Kennedy's 1961 white ensemble and made it look like a dishcloth by comparison. America is in capable hands.

Aside from being a Princeton and Harvard scholar, a lawyer and a public servant, a successful First Lady must also be a fashion icon. This one has been practising. One Gap dress sold out hours after she was seen wearing it. A yellow dress from J Crew became the store's bestselling outfit of 2008 – despite the fact that nobody looks good in yellow. But Mrs O has some hard acts to follow.

Mamie Eisenhower, who was First Lady between 1953 and 1961, was a nation's grandmother and a 1950s housewife all in one. Her sugar pink inaugural gown, with matching gloves and handy clutch bag, said it all.

Mrs Eisenhower was known as a gracious hostess – though not to her successor, Jackie Kennedy. It's as if she knew that history would forget the dowdy pink one who preceded the most glamorous woman in the world. Starting as she meant to go on, Mrs Kennedy designed her own off-white, sleeveless gown. Later, the President mused: "I am the man who accompanied Jacqueline Kennedy to Paris."

"Lady Bird" Johnson was the first First Lady to have a press secretary and chief of staff of her own – she probably needed them to explain the canary yellow silk tent that she wore for her husband's inauguration.

In the early 1970s, it was up to Pat Nixon to show that a globetrotting humanitarian could nip into a combat zone and still get home in time to iron her husband's trousers too. In 1969, her gold and silver inauguration gown in mimosa silk satin was light and feminine – but with an unbreakable carapace of Austrian crystal. This was one up on her successor, Rosalynn Carter, who in 1977 wore the same gown that she had worn at Jimmy Carter's gubernatorial celebrations. She may be in the US National Women's Hall of Fame, but she is remembered for buying off the peg.

Nancy Reagan, unfortunately, redressed this balance. Her inauguration frocks, estimated at $10,000 in 1981 and $46,000 in 1985, made her famous for Hollywood glamour. They also made her famous as the kind of person who spent $210,399 on White House china during a recession.

Skipping over fashion refusenik Barbara Bush, we come to Hillary Clinton. In 1993, her purple sparkly stunner should have pegged her as a woman who was itching to come out of her husband's shadow.

Curiously, one of the best dressed First Ladies in recent years was Laura Bush, whose ice-blue Oscar de la Renta gown at her husband's second inauguration, in 2005, was a masterpiece of understatement. Mrs Bush's approval rating was consistently higher than her husband's – something she achieved with quiet reserve and by never putting her foot in it, whatever she wore.