On Thursday night, the Sex Workers Project celebrated its 15th anniversary at a club in West Manhattan, complete with burlesque dancers and an auction. And the group -- the only organization in the United States dedicated to serving both sex workers and victims of human trafficking -- had a lot to celebrate. Across the country and around the world, sex workers and their allies have been fighting for the decriminalization of prostitution, and the right to do their jobs safely and without interference from law enforcement. In 2016, the tide might be turning in their favor.

Sex work -- an umbrella term that encompasses everything from the adult film industry to high-end escorting to stripping and street prostitution -- cuts across every socioeconomic divide. An estimated 1 to 2 million people exchange sex for money in the U.S., and their lives are often governed by the stigma -- and sometimes violence -- they face because of their jobs. Prostitution is a criminal offense in the vast majority of the country -- even having condoms in your pocket can be enough evidence to be arrested for prostitution in some cities (putting sex workers at increased risk of HIV). Sex workers are at higher risk of sexual assault, but they can’t seek police help in places where sex work is criminalized.

In the United States, prostitution is illegal outside of Nevada, where so-called "brothel" prostitution is permitted in 12 counties. The FBI estimates that 56,600 people were arrested for prostitution in 2012, the most recent year for which data is available. Many activists who oppose the decriminalization of sex work point to human trafficking and "pimping" -- operating a prostitution business or transporting a prostitute to a customer -- as the real crimes. But Maggie McNeill, a 49-year-old "career sex worker,” and other advocates say that for them, "pimping" and the crime of "brothel keeping" -- the act of maintaining a location for prostitution -- are often simply easy avenues for law enforcement to crack down on sex workers by calling it "sex trafficking."

"I have an apartment where I discreetly meet clients; the law calls that 'brothel-keeping,'" McNeill told MTV News. "If I let another girl use that apartment, that's 'pimping.' It's also 'pimping' if I give her a ride or a referral to a good client. And if another friend calls me to participate in a duo with her (i.e., her client wants to see two ladies at once), that makes her a 'pimp' too. If I gave her a ride to that client's house, we could actually be accused of 'pimping' each other.”

In many states, the act of prostitution is a misdemeanor offense -- but "pimping" and "brothel-keeping" can result in years of prison time. And sometimes, law enforcement itself is the real danger: Almost a third of street-based sex workers interviewed in New York City said that they’d received threats of violence from police officers. In Oakland, California, law enforcement officials allegedly sexually assaulted an underage sex worker for over six months, leading to the resignation of two police chiefs in Oakland; a third was fired.

The Sex Workers Project provides legal and social services to sex workers, from representing them in court to helping them find safe housing. But the group’s goal is to fight for the decriminalization of sex work in the States -- the best way, the group believes, to protect the needs and rights of sex workers. Kate D’Adamo, National Policy Advocate for the Sex Workers Project, told MTV News that SWP supports decriminalization -- "pulling the laws off of the books," rather than legalization -- which would permit some forms of prostitution (red-light districts, brothel-based prostitution) and not others (street prostitution).

Worldwide, only New Zealand and the Australian province of New South Wales have decriminalized prostitution, but SWP and other groups, including the National Center for Transgender Equality and the Red Umbrella Project, believe that decriminalization is a better way forward. "Legalization ends up remarginalizing the same people who are already marginalized,” D’Adamo says, adding that "if you have to be within a brothel, if the brothel isn’t hiring, if it takes a licensing structure that costs $500, if you don’t have certain things that are often dependent on poverty or documentation status, you can still be arrested for those same crimes," putting poorer people, people of color, and trans people at significant risk.

Some countries criminalize the buying of sex, but not the selling -- the so-called "Nordic model." In Sweden, it’s been illegal to purchase sex since 1999. Proponents of the Nordic model say that it has reduced prostitution and human trafficking, but sex workers believe that the Nordic model just puts them at increased risk, costing them their livelihoods and forcing them into dangerous situations in order to make enough money to survive. Outreach specialists can’t get to them because the work sex workers are doing is illegal to buy, and sex workers are often forced into more remote areas -- and faster, more dangerous transactions with riskier clients -- to avoid law enforcement. "All you’re trying to do," D’Adamo says, "is secure a client and then get the hell out of there."

Moreover, the Nordic model has never been used in a country where it was illegal to sell sex in the first place -- in the United States, the model would just increase penalties and policing. And by penalizing clients, the Nordic model implies that adult sex workers -- many of whom are acting of their own free will -- are incapable of giving consent.

Decriminalization is gaining ground: In 2015, Amnesty International voted to support decriminalization of sex work worldwide, saying in a statement that laws regarding prostitution should be "refocused on making sex workers' lives safer and improving the relationship they have with the police while addressing the very real issue of exploitation."

McNeill has been a full-time sex worker for 19 years, blogging about her experiences since 2010. She’s become an activist and a voice for sex workers in the media because she believes that their stories need to be heard. "The more people get to see sex workers as real individuals rather than cardboard villains, vixens or victims, the less they'll support laws designed to harass, imprison, exile, or 'rescue' us," she says.

"If I had just a few minutes with a person, I'd tell her that sex work is not intrinsically different from other forms of sex or other forms of work," she says, adding that sex workers aren’t criminals or victims but "ordinary people." "We choose sex work because it's the best form of work for our needs. Other people might make different choices, but for us, sex work best fits what we sex workers need from work." And McNeill says that if sex isn’t against the law, prostitution shouldn’t be, either. "If an act isn't illegal, why should it become illegal just because busybodies don't like my reason for doing it?"