NEWARK, N.J. (AP) — Two Internet groups are suing to block a New Jersey law concerning online ads for underage sex workers, saying libraries and other third-party service providers could be at risk of prosecution.

The law, signed by Gov. Chris Christie in May, is part of legislation aimed at cracking down on human trafficking.

But the Internet Archive, a San Francisco-based nonprofit, and, a classified advertising website, sued, claiming the law violates a 1996 federal statute that says service providers can’t be responsible for most things users do online.

The parties say the law could hold third-party providers, including libraries and Internet companies, liable for anything sent over their systems, making them responsible for policing content.

“Everyone is highly motivated to stop sex trafficking,” said Matt Zimmerman, an attorney with the Electronic Frontier Foundation, a nonprofit Internet freedom group representing the Internet Archive. “The question is, How do you do that, and can you lean on the intermediaries in the middle and make them do law enforcement’s work in trying to crack down on this stuff?”

The Internet Archive and successfully blocked a similar law in Washington state last year. A similar bill is pending in the Connecticut legislature. In January, a Tennessee judge ruled a similar law is unconstitutional and curbs free speech.

The New Jersey law states that a person can be found guilty of advertising commercial sex abuse of a minor if “the person knowingly publishes, disseminates, or displays, or causes directly or indirectly, to be published, disseminated, or displayed, any advertisement for a commercial sex act, which is to take place in this State and which includes the depiction of a minor.”

A federal court judge issued a temporary restraining order June 28 prohibiting the New Jersey law from taking effect while the lawsuit is pending. It would fine providers at least $25,000.

“As part of a comprehensive effort to protect victims of human trafficking, the Legislature sought to limit the marketing of childhood prostitution,” said Lee Moore, a spokesman for New Jersey Acting Attorney General John J. Hoffman. “Neither the Constitution or federal law prohibits the State’s efforts, and we will continue to defend the statute’s legality.”

The legality of the bill was discussed while its merits were being debated. It passed the legislature unanimously.

“Quite frankly we did expect a challenge,” said the bill’s sponsor, Assemblywoman Valerie Vainieri Huttle. But putting a burden on the publisher of ads for underage sex workers “far outweighs the life of a child that could be taken and scarred forever,” she said.

A group of attorneys general is drafting a letter asking Congress to amend the 1996 law, section 230 of the Communications Decency Act. The attorneys general want the law to be able to apply to state cases and law as well as federal.

“This is part of a broader political strategy to provide state attorneys general with ammunition to try to amend section 230,” said Jeffrey Hermes, director of the Digital Media Law Project at the Berkman Center for Internet and Society at Harvard University. “This is a threat to the operability of the Internet of quite significant dimensions. It opens holes to the law that protects the core functionality of the Internet.”

A hearing on the New Jersey law is scheduled for Aug. 9.

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