The Electronic Frontier Foundation (EFF) has sued the federal government and Attorney General Jeff Sessions to challenge the Allow States and Victims to Fight Online Sex Trafficking Act (SESTA-FOSTA), signed  into law by President Donald Trump in April.

The lawsuit was filed on Thursday. Woodhull Freedom Foundation et al. v. United States is the first action to challenge SESTA-FOSTA, which critics contend puts sex workers at greater risk, but advocates claim will cut down on human trafficking, particularly of children.

The plaintiffs in Woodhull Freedom Foundation et al. v. United States includethree organizations – Human Rights Watch, Woodhull Freedom Foundation and the Internet Archive – and two individuals. The suit claims they are engaged in constitutionally protected speech.

The complaint by the EFF claims SESTA-FOSTA violates the First and Fifth Amendments by preventing its plaintiffs from using online forums for fear of criminal charges. It argues that the legislation resembles the anti-indecency provisions of the Communications Decency Act, said provisions ruled unconstitutional by the Supreme Court in 1997.

Non-profit EFF is a a civil liberties organization specializing in online and digital technology. It has battled SESTA-FOSTA since its introduction to Congress in 2017. That proposal made it a crime to operate or manage a website that “promotes or facilitates prostitution,” a grey definition which increases potential liability for sites that host any sexually oriented content, including discussions of it.

Many sites have taken a cautious route in the wake of the new law. Craigslist took down its personals section, while Reddit banned certain sex-oriented subreddits.