POLITICAL PUNDITS may have been surprised at the sight of the presumptive Democratic nominee Sen.

Barack Obama

's fist-bumping his wife, but what

Michelle Obama

had on that night in Minnesota was only slightly less remarkable.

But with all the talk examining the cultural significance of a possible U.S. president's exchanging a little tap with his significant other, her attire got overshadowed somewhat. Her dress was a sleeveless sheath, and it was purple - not Nancy Reagan red or blend-into-the-background blue, but a color long associated with royalty and power. And instead of wearing this head-turning color in a safe but yawn-producing business suit, Michelle was dressed down, in a sleeveless, collarless shift, revealing well-toned arms that prompted a friend of mine to remark that she "must be pumping iron while conducting business on speakerphone."

Seeing it on TV, it was hard to tell whether the garment was haute couture or an off-the-rack creation. But the result was the same - a garment stunning in its simplicity. We're not used to seeing wives of presumptive nominees of either party chance it by making bold fashion statements. Usually, the goal is to blend into the background so as not to upstage the candidate. The only role expected of the wife is to gaze adoringly at her husband while he's speaking and also to pretend she hasn't already heard him utter the same catchphrases before.

It turns out, the dress was made by Maria Pinto, a former Geoffrey Beene assistant. According to the New York Times, it goes for about $900, but the designer's office, which has been flooded with requests for it, told me it's priced only upon request. Yesterday, through e-mail, the designer said that she considers Michelle Obama a "client and dear friend" and that she's been designing for her since before her husband's run for the Senate in 2004. Called the "Sidona Dress," it's available in lots of colors and exclusively through the designer (312-602-2630).

"Choosing items that are always modern and chic, Mrs. Obama possesses a natural and unpretentious sophistication, which is reflected in her clothing," Pinto wrote. "But what I love most, is that at the foundation of this fabulous woman is an unbelievable brilliance and eloquence coupled by the grace and beauty of a dancer. She is captivating in any arena. Style aside, it is her wit and intellect that make her one of the most extraordinary women we could ever hope for in the White House."

Michelle Obama, perhaps unwittingly, crossed another barrier, too, by at least appearing to be barelegged when she walked onstage after her husband's speech. As recently as last week, I was reading a discussion in the Wall Street Journal about whether or not it's OK for women not to wear pantyhose in certain arenas. Typically, the decision whether to hose it or not breaks down along generational lines. Some older women stick with tradition, and might even need the camouflage, but, increasingly, their daughters just flat-out refuse - regardless of what industry they're in.

"The thing with Obama is authenticity," pointed out Danielle Celena Belton, who runs a humor blog called Black Snob. "You honestly feel like she dressed herself. She wasn't scripted. She was wearing what she felt like wearing. It wasn't about fitting the traditional mode."

Of course, there's still a lot we don't know about Michelle Obama, which is why we spend way more time than we should analyzing her fashion choices or trying to figure out what she meant when she makes an occasional verbal slip. My sense, though, is that this is a woman comfortable with making up her own rules as she goes along. Maybe she realizes that since she's taller than average, the cookie-cutter thing's not going to work for her, so why even try?

As for me, I can't wait for Abs or some other imitator to come up with a knock-off version of that dress. *

Have you peeped a hot trend that hasn't been reported? E-mail heyjen@phillynews.com and let me know what you know.