The silver-blue tulle gown, embroidered with bugle beads and outlined in Austrian crystals, is the stately if conventional centerpiece in a wardrobe the first lady will wear during four days of festivities in Washington, including 10 balls, candlelight dinners, a parade and fireworks.

In addition to de la Renta, a longtime couturier to the fashionable elite, designers for her wardrobe include Carolina Herrera, who fills a similar niche, and by Peggy Jennings, a little-known designer who has been quietly wardrobing the first lady for two years.

The president's daughters, Jenna and Barbara, will be dressed by Badgley Mischka, Lela Rose, Derek Lam and de la Renta for the inaugural festivities.

Laura Bush's wardrobe is sure to be studied for clues about her evolving personal style and even for hints about the overall tone of the White House in the next four years. ''The first lady is certainly a reflection as to the man holding the office,'' de la Renta said. He was reluctant to ascribe special significance to Laura Bush's sartorial choices, which are more glamorous than they have been in the past, and, indeed, more glamorous than anything the White House has seen since the Reagan years.

But another observer, Catherine Allgor, a historian of first lady style, suggested that in anointing de la Renta and Herrera, mainstays of taste among wealthy women, Bush appears to be displaying a growing awareness that ''her power is entrenched.''

''She has gone from being just folks to being a bit imperial, assuming a bit more of a queenly role,'' said Allgor, the author of Parlor Politics: In Which the Ladies of Washington Help Build a City and a Government (University Press of Virginia, 2002).

The first lady, who during her husband's first term sometimes professed an aversion to fashion, preferring straight-fitting, neutral and matronly suits that concealed her shape, has reversed herself in recent months. She has embraced New York's Seventh Avenue to the point of visiting de la Renta and Herrera in their design showrooms - a departure from White House tradition. She will pay for all of her and her daughters' dresses, said her press secretary, Gordon Johndroe.

Bush watchers point out that de la Renta and Herrera are light years in sophistication from the image Laura Bush conceived four years ago by employing Michael Faircloth, a Texas designer, to make her wardrobe for the inauguration. Faircloth, little known at the time, made her a tight-fitting scarlet lace gown.

The dress was much deprecated by style-watchers. Since then, Bush has projected a more feminine and worldly image, and she seems more conscious of her role as a symbol of state. ''Mrs. Bush has very successfully created a strong iconography for herself,'' said Hamish Bowles, an editor of Vogue who was curator of an exhibition on the style of Jacqueline Kennedy in the White House for the Metropolitan Museum of Art in 2001. ''She is less provincial, more urbane, but still on the safe side,'' he said, adding that her image is ''calculated not to frighten the horses.''

There is nothing intimidating about de la Renta's ice-blue ball gown. To judge from the sketches released by the White House, it has a reassuringly familiar look, reminiscent in spirit and in silhouette of the gowns James Galanos designed for Nancy Reagan in the 1980s.

Since 2001, Bush's fashion sense has ripened with nudges from her daughters and design world friends. She appeared with President Bush to claim victory in the election in November dressed in a pale pink suit by Peggy Jennings that discreetly showed off her figure, slimmed down to a size 6, Jennings said over the weekend. Jennings has designed a rose-colored hand-beaded lace gown that the first lady will wear to several candlelight dinners Wednesday.

In addition, she will wear a raspberry-colored striped silk shirtdress by Herrera to the Texas State Society's ''Black Tie & Boots'' ball Wednesday.

In Vogue this month, the first lady is photographed modeling a streamlined Herrera suit and a deep blue silk shirtwaist gown by de la Renta, accessorized with amber beads that match her hair, which was clipped for a youthfully breezy look by Sally Hershberger, who shears the heads of the Hollywood elite.

Bush seems determined to appear more youthful in her second term. Through her press secretary, Johndroe, she acknowledged that she is increasingly taking style cues from her 22-year-old twin daughters, who have been dressed by New York arbiters of hip like Zac Posen and Narciso Rodriguez. ''Mrs. Bush has really enjoyed working with some of the designers Barbara and Jenna favor,'' Johndroe said.

The glamorization of Laura Bush's image began as far back as the aftermath of the 2001 inauguration. Preparing to have her photographed for Vogue, Anna Wintour, the magazine's editor, requested that de la Renta provide some clothes. The designer, who had dressed Hillary Clinton in the White House, balked at first. ''I didn't think Mrs. Bush would want to wear my clothes,'' he recalled. ''I had been so closely identified with Mrs. Clinton.''

But Bush, it seemed, had notions of her own. ''She arrived at the shoot with a red suit of mine that she had bought in Austin, Texas,'' de la Renta said, and specifically asked to see more of his work. He has been dressing her since.

What he did not acknowledge is that coaxing the first lady out of the prim, upholstered-looking suits she once favored is a job requiring a measure of political savvy and a vast reservoir of tact.

''You have to be very diplomatic to dress a president's wife,'' said Arnold Scaasi, who has wardrobed his share of them, including Barbara Bush, Jacqueline Kennedy and Mamie Eisenhower. ''You must tell them nicely that they didn't look too great before you, and would look so much better now if they would only listen to you. ''

Jennings, who met with Laura Bush earlier this month for a fitting in Manhattan, prides herself on having persuaded the first lady to wear more form-fitting, feminine clothes. ''The first gown that I made for her I took the liberty of making the neckline too low,'' Jennings said. She recalled that Bush responded with tact. " 'You know, Peggy,' the first lady told me, 'maybe this would look nicer if the neckline were a little higher,' " Jennings recalled, adding that she recut the dress.

For designers, inaugural commissions are well worth it. The first lady's ball gown is enshrined at the Smithsonian Museum, where it is seen by streams of visitors. And for prestige, the commission knows no equal, not even a dress for the Oscars. ''Designing for the first lady is the best sort of attention you can get,'' Scaasi said, translating into dresses that are widely copied and widely ordered by stores.

What will the president wear?

President George W. Bush will wear a business suit to his swearing-in rather than a more formal morning coat - a style last worn by President Reagan.

The president has not added a new suit to his wardrobe for the swearing-in, according to the White House. But he will maintain a tradition established in 1995 when he was first sworn in as governor of Texas. He will wear a pair of gold cuff links inset with platinum Navy wings that were given to him by his father. President George H.W. Bush received them in 1943 when he was commissioned into the armed services in Corpus Christi, Texas.

This will be the fourth swearing-in to which his son has worn them.

- The Washington Post