It’s a sweltering July day in Union Square, an eclectic hub in downtown New York City. A sweaty violinist nods as a woman drops a dollar in his case. Skaters squirt each other with bottled water and do tricks on the subway stairs. Tourists meander through the farmers' market where, amid the hustle and bustle, a topless young woman carefully inspects a head of lettuce, her perky breasts hovering above the produce.

“You look good!” a man calls out to her. “Why shouldn’t a woman be able to walk around topless? Right? I’m allowed to look, right?”

Moira Johnston and her breasts have become pseudo-celebrities in downtown Manhattan this summer. They’ve been covered extensively in local media outlets. They’ve reassured Big Apple denizens that New York City is indeed the greatest place on earth. They’ve even become celebrities to celebrities. Several weeks ago, Michael Lohan, father of actress Lindsay Lohan, tweeted a picture of a UPS man reacting to Johnston’s toplessness, which Lindsay subsequently retweeted to her four million followers.

While most people are enjoying the free sights, Johnston, 29, a topless dancer originally from Philadelphia, has a more political agenda for doffing her top in daylight hours. A self-described “topless activist,” she is trying to raise awareness of a little-known New York state law that permits women to be topless anywhere men can do the same.

It all started in January at a yoga studio in Manhattan, when Johnston was banished after she took her top off in class. Some of the other yogis complained to the owners about her bare breasts, but Johnston thought it unfair that men be allowed to go topless in Downward Dog while women are forced to keep their mammaries in their Lululemon tanks.

Johnston wasn’t, in fact, committing a crime.

It’s been legal for a woman to go topless in public since the 1992 case of People v. Ramona Santorelli and Mary Lou Schloss. In 1986, the defendants were cuffed in a Rochester, N.Y., park for violating a law prohibiting women from showing “that portion of the breast which is below the top of the areola.” (For those who need to brush up on their breast terminology, the areola is the colored skin surrounding the nipple, e.g., “Kate Moss has small areolas.”) Santorelli and Schloss argued that the law was “discriminatory on its face since it defines ‘private or intimate parts’ of a woman’s but not a man’s body as including a specific part of the breast.” The New York Court of Appeals ruled in their favor.

Johnston, who was jailed earlier this spring when she refused to put on a shirt outside a children’s park in Union Square, is one of several women to be wrongfully arrested since the law was enacted. In 2005, Jill Coccaro was arrested for hanging loose on Delancey Street in New York City, but sued the city and received a $29,000 settlement. And in early July notorious flasher Holly Van Voast was detained on the 20th anniversary of the law’s enactment for going topless outside of Hooters in midtown Manhattan.

Johnston didn’t reap any such awards from her arrest, but she’s dedicated to her cause. She’s been strolling around New York City without a shirt since early May and has no plans to stop any time soon. She’s also filed legal complaints against 13 yoga studios, including the one that told her to cover up, which has since made it mandatory for women and men to wear shirts.

“The New York State Division of Human Rights is working on the complaints,” Johnston, 29, tells The Daily Beast on a recent steamy afternoon in Union Square, her usual hangout, where you might see her strolling sans shirt with a friend or buying sauerkraut juice from a market vendor. “These yoga studios should know it’s a civil rights violation.”

Privately owned institutions are allowed to make their own rules as long as they apply equally to all people and don’t discriminate against sex or race. “So it’s basically as serious as saying black people aren’t allowed to take off their shirts but white people are,” Johnston says.

“I want women to know their rights and to give them the courage to go topless too,” she says when asked what she hopes will be the outcome of her cause. “It’s not that I want everyone to take off their shirt, but I’m supporting a woman’s choice to do it and think every woman should do it on her own terms.”

It’s great that Johnston wants to exercise a woman’s right to bare breasts, but of all the equality issues she could be fighting for—maternity leave, health care, equal wages, the right to choose—hers seems like a battle in a war that’s been won. As one man asked her in Union Square, “Isn’t that already legal?”

Let’s just say she’s not exactly the next Gloria Steinem. Johnston politely responds to people’s questions, speaking with an air of emotional detachment and giggling often. “I find that this role is uniquely suited to me,” she says. “It’s something that I care about and think is important enough that I’m pursuing it.”

Though she’s not currently associated with any activist groups, she was briefly involved with Act Up Philadelphia, an organization that supports people with HIV and AIDS, and she also volunteered in the LGBT community. She put herself through college, starting her undergraduate career at Moore College of Art and Design, an all-women’s visual-arts school in Philadelphia. “My artwork was going to be about social change,” she said, particularly women’s rights and child welfare. She ultimately graduated from Temple University with a B.A. in sociology and ever since has been working as a topless dancer to pay the bills.

“Dancing is part of what inspired me to go topless in other contexts,” Johnston explains, adding that doing so subverts the idea that a woman’s breasts are exclusively sexual or commercial territory. “That’s part of the breastfeeding issue—there’s a social stigma associated with feeding your children and our body parts are more than just sexual and commercial. It’s okay if they’re sexual too. They’re both.”

Thanks to her nighttime job, Johnston is accustomed to people staring at her chest, and her demonstration has been met with mostly supportive reactions. Men give her high-fives and two thumbs up. Members of both sexes engage her in conversation about her cause. One woman asked if they could go topless together.

Of course there are exceptions, such as the man who told her he’d just gotten out of prison and was going to hurt her.

“I considered carrying mace [after that encounter], but that’s absolutely not a common occurrence,” Johnston says, adding that she’s never been groped or assaulted. “Most people are fairly respectful, at least in terms of my physical space.”

Posing for a picture with a man who throws his arm over her shoulder, Johnston kindly asks that he not touch her. She’s used to the picture-taking by now (at least eight men asked to pose with her in the hour that we were together).

“I recently read that the underwire in bras can cause breast cancer,” Johnston says, while ignoring an older woman who shakes her head and mutters to herself as we wait to cross the street outside the park.

“You can’t do that in New York City!” a man says and then scurries away. “It’s legal!” Johnston calls after him nonchalantly.

“Oh yes you can,” another woman chimes in. “Good for you.”