In June 1999, Martha Stewart, doyenne of domestic entrepreneurship, wore a pink silk Ralph Lauren pantsuit to a White House dinner honoring the president of Hungary. Certainly other women had attended White House events in trousers -- soft, billowy and barely distinguishable from a skirt. But Stewart was unapologetic in crisp, tailored pink capris and a short matching jacket. The Post described her ensemble as "summery, but perhaps not the most appropriate attire for a state dinner." Even etiquette expert Letitia Baldrige expressed displeasure at Stewart's sense of protocol.

For the past 125 years in Washington, fashion has never been a question of pure aesthetics. It has always been a complicated mix of protocol, gender debates and power. The essential question here is ultimately: Who wears the pants?

In the early part of the 19th century in Washington, as elsewhere in the country, trousers were considered men's apparel -- off-limits for respectable women, who wore dresses even when they participated in sports. Even today, trousers carry with them an echo of their history -- they have been borrowed from the boys.

In slipping on pants, women such as the suffragettes, Marlene Dietrich, Katharine Hepburn, Colette and Coco Chanel -- who all wore trousers long before they were deemed respectable -- were also taking on many of the most admirable traits of masculinity. During both world wars, women wore pants when they were pushed into the workforce to do the strenuous, but necessary, industrial jobs that men had left behind. Their trousers symbolized their resilience and competence.

In 1966, designer Yves Saint Laurent introduced le smoking, a feminine version of a tuxedo. A few seasons later, he launched women's pinstripe suits. And the couture ateliers helped to fuel a revolution. In the mid-'60s, when New York socialite Nan Kempner was denied entry to La Cote Basque because of her black Saint Laurent pantsuit, she promptly dropped her trousers to the floor and marched into the restaurant in nothing but the remaining tunic.

The drama over the popularization of women in trousers was extreme, yet Washington embraced the trend. "In those days, if Yves Saint Laurent said it was to be, people grabbed it," says Peter Marx of Saks Jandel, whose family brought YSL ready-to-wear to the Washington area.

Veteran Saks Jandel fashion expert Val Cook recalls attending a party in Rome in the late '60s and having designer Hubert de Givenchy look at her pajama-pant ensemble and pronounce her the most fashionable woman in the room.

But while the fashion-conscious applauded trousers, mainstream Washington shunned them. Nina Hyde, fashion editor of The Washington Post, once told of being reprimanded for wearing trousers in the mid-'60s. She had been in Europe, covering the collections, and had seen designer Andre Courreges' collection of architecturally inspired tunics and pants.

"I remember returning from Paris and buying at Bergdorf Goodman in New York, the moment it hit the racks, a copy of the Courreges pants outfit, interpreted in navy wool knit by Kimberly Knitwear," Hyde wrote in The Post in 1989. "I remember, just as clearly, wearing my prize to the office one day and being told by my boss, Richard Hollander, editor of the Washington Daily News, 'If you weren't fashion editor, I'd send you home for wearing pants to the office.' "

Hyde was allowed to stay at her desk, but it would be years before trousers were commonplace female attire in the offices of Washington.

Yet the fashion industry pressed on. Giorgio Armani launched his collection of easy, unconstructed pantsuits for women in 1976. The pleated trousers and jackets, cut from menswear fabrics, eventually became the '80s power uniform for many women.

Yet inside the Beltway, women favored the John T. Molloy "Dress for Success" power style, which was to dress like a man but with a skirt in place of pants. "I remember, years ago, when we lived in that uptight little skirt suit with the bow at the neck. It was the career woman's and the volunteer's outfit," says Washington philanthropist Buffy Cafritz.

Cafritz was one of the early adopters of pantsuits. "I remember buying a Bill Blass pair of checked pants -- pants and coat to match -- and that was the beginning. I must admit I was a little uncomfortable at first because I was one of the pioneers at meetings," she says. "The only comments I got were from my own mother. She thought it was . . . too masculine a look. It was a shock to her the first time she saw me in a pantsuit."

But tradition couldn't compete with the lure of comfort and ease. Slowly, trousers infiltrated Washington society, just as they had in other cities.

Official Washington was far more stubborn. Nancy Reagan was ridiculed for wearing pants -- James Galanos black satin knickers, to be exact -- to a 1982 party at the American Embassy in Paris.

In 1992, Life magazine was photographing a cover story about women in the Senate. The premise was "If Women Ran America," and so 98 women and two men were asked to stand on the steps of the Capitol to show how the Senate would look if the gender ratio were reversed. To make the photograph as realistic as possible, one woman had to be slightly camouflaged because she was wearing pants.

And even then, trousers were not allowed on the Senate floor.

"We've heard from women staff that in the 1980s, if they came in to work -- if they were called in on an emergency basis -- they needed to keep a dress to put on quickly or they had to borrow one if they had to appear on the Senate floor," says Richard A. Baker, the Senate historian.

But if pants could be worn to church, why not to the Senate? In 1993, Carol Moseley-Braun and Barbara Mikulski took a stand and wore trousers on the Senate floor.

The Post wrote: "When the Democratic senators started showing up in pantsuits, it didn't take long for floor attendants and support staff, who had been forbidden to wear pants, to ask for a break. Shortly thereafter, Sergeant-at-Arms Martha Pope issued an amendment to the dress code."

It was a victory that allowed women more comfort, but also removed a visual cue that had suggested female senators be dealt with based on gender before anything else. In 2000, when Hillary Rodham Clinton celebrated her victorious Senate campaign, she wore the standard business uniform that had become her trademark: the dark pantsuit.

But trousers still have not completely shattered their link to masculinity. Indeed, some would argue that what makes a woman so sexy in a tuxedo is the blurring of gender lines. A woman in a pantsuit is often still seen as more informally dressed than a woman in a skirt, as if she has not fully acknowledged the importance of the situation.

"I don't think there's any place I haven't worn a pantsuit," Cafritz says, noting that she has worn them to the White House. "But I draw a line at a real dressy black-tie event. I still wear an evening dress. . . . Also, the grandeur of the building sometimes demands an evening dress."

Here, authority most often is gained by using the rules to one's advantage, not in launching a campaign against the rules themselves. At least this is so when it comes to fashion.

On any given workday, women wear trousers and no one bats an eye, for this is the uniform of a contemporary working woman. But in situations that are steeped in formality or full of pomp -- when women are ladies and men are gentlemen -- the old markers of gender apply. And few cities have more pomp than Washington. People still find pleasure and reassurance in the costumes of civility. Would Cinderella be such an icon had she worn evening pants to the ball? Rarely does a bride walk down the aisle in a white pantsuit. Girls still search for prom dresses, not prom pants. And first ladies, the embodiment of ceremony and symbolism, know that the public -- especially the old guard -- looks askance at trousers.

In January, first lady Laura Bush said she often receives letters, from "mostly elderly people . . . who say that the first lady should only wear skirts." Of course, as she made this admission, she was wearing a sensible black pantsuit.

Bathing costumes could stop no more than 6 inches above the knee at the Tidal Beach Bathing Beach in 1922, by order of the District's superintendent of Public Buildings and Grounds. Officer Bill Norton checks one suit.A state dinner or a backyard barbecue? Martha Stewart's capri pants for a 1999 White House dinner were deemed a very bad thing.Nancy Reagan drew snickers for her choice of knickers for a 1982 party at the American Embassy in Paris.Buffy Cafritz (shown with Philip Stern, left, and Michel Legrand) was an early adopter of pantsuits, wearing them as early as May 1967.