Human rights advocates tend to focus on people in grim circumstances. “Like many feminists, I’m conflicted about sex work,” says Liesl Gerntholtz, executive director of the women’s rights division at Human Rights Watch, which took a stand in favor of decriminalization four years ago. “You’re often talking about women who have extremely limited choices. Would I like to live in a world where no one has to do sex work? Absolutely. But that’s not the case. So I want to live in a world where women do it largely voluntarily, in a way that is safe. If they’re raped by a police officer or a client, they can lay a charge and know it will be investigated. Their kid won’t be expelled from school, and their landlord won’t kick them out.”

Amnesty and Human Rights Watch, along with other groups that support decriminalization – U.N.AIDS, the World Health Organization, the Global Commission on H.I.V. and the Law and the Open Society Foundations – acknowledge that there can be grave harms associated with the sex industry, but say that they see changes in the law as a precondition to reducing them. Last year, an analysis in The Lancet predicted that “decriminalization of sex work could have the largest effect on the course of the H.I.V. epidemic,” by increasing access to condoms and medical treatment. Governments can free themselves to crack down on trafficking and under-age prostitution, human rights advocates argue, if they stop arresting consenting adults.

It’s a pragmatic argument. But the sex-workers’ movement also hinges on an ideological conviction – the belief that the criminal law should not be used here as an instrument of punishment or shame, because sex work isn’t inherently immoral or demeaning. It can even be authentically feminist. “Once you’ve done it, you always know: When it comes down to it, I have everything I need to survive,” says Anna Saini, a former sex worker who is now a sex-worker activist and law student living in Brooklyn. “That’s powerful.” This view poses a deep challenge to traditional Western feminism, which treats the commercial sex industry as an ugly source of sexual inequality.