The sheath: a particular brand of female-anchor sexy.

Mika Brzezinski attends the opening of the Milly Madison Avenue boutique in May 2011.

Photo by Thomas Concordia/Getty Images

The female newscaster of today does sexy in a very specific way. It is sleeveless sexy, an age-defying, loose-skin-defying means of telling the world that she worked out this morning and every morning, long before she went to hair and makeup and started broadcasting the nation’s news, long before viewers even considered waking up.

The sleeveless sheath dress, now ubiquitous on cable and local news, and especially beloved by morning news programs, is as much a uniform for TV newswomen as androgyny was in the mid-’90s, when boxy blazers and short hair reigned. Only seven years ago, when Katie Couric took over the CBS Evening News, critics worried whether she might be scandalizing the nation by showing too much leg. Now, legs are the least of it. They’ve been joined by bare arms and dresses so form-fitting that Couric has said many of her colleagues look like they’re going “clubbing.” The seriousness of the news (OK, seriousness sometimes) has been completely decoupled from the seriousness of the attire of the women presenting it. Only in this precise sartorial moment could Melissa Harris-Perry, the eggheady Tulane professor who has her own show on MSNBC, tackle the angsty politics of black hair in a fitted, halter-neck dress suited to a night out in the meatpacking district.

The sleeveless look is especially jarring this time of year. On Fox News, which has long pushed the sex appeal of its female talent further than other networks, it is typical to see a suited man next to a woman outfitted for lunch on some sunny Roman piazza, as if the colleagues are dressed not only for widely disparate occasions but for different climates as well. On Today, Kathie Lee Gifford and Hoda Kotb are typically sleeveless, sitting before windows that showcase people bundled up against the Manhattan cold. They also love to get loaded, on-air, well before the lunch hour. They are TV women, after all, observing rules neither of time nor of space.

There’s a reason why the women of TV news have embraced sleevelessness while treading carefully in matters like cleavage (sexy weather reporters aside). Bare arms read as a kind of smart-sexy, a look that women in positions of authority can pull off. Michelle Obama is responsible for this, as are socialites of the Manhattan cocktail circuit, for whom bare arms long ago became a currency of wealth and fitness. MSNBC’s Mika Brzezinski and Chris Jansing are fans of the look, as is CBS’s Gayle King, and CNN’s Brooke Baldwin. Fit arms are about control, a state of poised strength you work at—so much so that supermarket magazines have accused Madonna and Angelina Jolie of pushing their exercise regimes too far, featuring their ropy, veiny biceps right next to close-ups of some other unfortunate’s cellulite. But if cellulite and cleavage can read as sloppy, toned arms are the very opposite; they’re all about intention and control. Which is why newswomen get to show them off. They are appropriate for early risers and Ivy League overachievers—the sexiness of success rather than vulnerability.

And yet. It’s telling that we now expect sexy at all from our TV newswomen. We haven’t always. Beauty, sure. When Diane Sawyer appeared in the ’80s in an off-the-shoulder evening dress on the cover of Vanity Fair, the decision caused such a stir that she was moved to remind a reporter that “there were no tassels involved.” But if you look back at images of newswomen from the ’80s and ’90s, they were notable for what they didn’t show. When MSNBC launched in 1996, Couric covered everything but her face, wearing a turtleneck under her beige blazer for the virgin broadcast. And women who’ve been on the air for decades tend not to go bare, either because they think it inappropriate to do so at their age or because they were schooled at a time when TV reporters didn’t do such things. In either case, clothing confers dignity. You can’t imagine Christiane Amanpour leveraging her erotic capital on the air.

It does, after all, matter when female voices of authority disrobe. Baring one’s skin, whether it’s décolletage or arms, remains an indicator of seriousness—are you going to look at me, or are you going to listen to what I’m saying? Because, as the Washington Post pointed out last year in a story about the blazer disappearing from newswomen’s wardrobes, male viewers appear unable to do both. A 2010 study found that the sexier the female anchor, the less men retain of what she says. They literally see instead of hear her. Rachel Maddow has said this is why she maintains a “conveyor belt of gray blazers,” in order to look the same for every broadcast.

“Don’t focus on what I’m wearing,” Maddow says. “Focus on what’s coming out of my face.”

The more you think about sleevelessness, the more it reads as a fault line in a stressed and fragmented news industry. TV reporters have always straddled the line between news and entertainment—the path from model or actress or pageant queen (Sawyer was one) to TV reporter is a well-trodden one. But for shows desperate not to lose eyeballs, skin becomes a competitive edge. Thus, the form-fitting sleeveless sheath has become a kind of uniform of Fox News women, favored by Megyn Kelly, Gretchen Carlson, Martha MacCallum, Michelle Malkin, and others. And thus, when Kelly, a high-profile Fox News anchor, was asked by GQ in 2010 what she thought of the network’s shots of her behind a glass table, showing off her legs, Kelly replied casually, “Well, it’s a visual business. People want to see the anchor.” Her logic seemed to echo the wisdom of chairman Roger Ailes, who, as Liza Mundy has written, presides over a network that pushes a heavily made-up look sometimes dubbed “Fox glam.” Quoting journalist Gabriel Sherman, Mundy suggested that Ailes, a one-time Broadway producer, is especially attuned to the entertainment aspect of television news. “The colors are brighter, the camera angles faster,” Sherman told her. “Everything pops on the screen more, every­thing is eye candy.”

I should mention that, for that same GQ story, Kelly posed wearing only a black slip and 4-inch red Louboutins, her bosom erupting from her bra. (Headline: “She Reports, We Decided She’s Hot.”) No tassels involved, but just barely.

Sleevelessness has become so commonplace, you barely notice it anymore. It’s been adopted even by newswomen who are acutely aware of the symbolism of their clothing, as well as the collapsing distinction between news and entertainment. As co-host of MSNBC’s Morning Joe, Brzezinski has on several occasions struck a blow against the trivialization of the news, most famously refusing to read a news item about Paris Hilton by shredding the script on air. She’s also told the Post how, during her first years on Morning Joe, network execs dressed her in clothing that was “short, skimpy, tight,” and she had to rebel and find her own look. It is clean, chic, and often sleeveless, generally more country club than nightclub.

Still, just a few months ago, Brzezinski posed for a Vanity Fair image that threw her self-awareness into doubt. In the photo, naughtily reminiscent of Michelle Pfeiffer’s piano-crawling scene from The Fabulous Baker Boys, the journalist wears a black sheath dress and poses provocatively on top of a table with one bare leg extended in the air. She gazes adoringly at Scarborough, who sits in a chair, fully suited, grinning at the camera. The message of her arms, not to mention those legs, is this: First and foremost, I am here to entertain you. Would you like me to sing or to dance?