(Bloomberg) -- The US Supreme Court turned away an appeal from victims of child pornography who claimed Reddit Inc. knowingly facilitates and benefits from images of child sexual abuse. 

The justices without comment left in place a ruling that affirmed Reddit can’t be held liable for violating sex trafficking laws when people use its platform to post pictures of minors being abused. 

It’s the latest in a string of victories for the country’s biggest social media platforms, which enjoy immunity from most lawsuits over online speech under a liability shield called Section 230. The Supreme Court earlier this month refused to limit the broad liability shield for social media companies, including Twitter Inc., Facebook Inc. and Alphabet Inc.’s Google. 

The 9th US Circuit Court of Appeals decision in Reddit’s favor marked the first time a federal appellate court weighed in on a 2018 amendment to Section 230, which was written to allow lawsuits against social media platforms over sex trafficking claims. 

The victims in the lawsuit argued the 2018 sex trafficking amendment, Allow States and Victims to Fight Online Sex Trafficking Act, or FOSTA, enabled them to sue Reddit for providing a platform for images of their abuse. They said Reddit “has engineered a social media platform where child pornography proliferates.” 

But the 9th Circuit said Reddit was still protected by Section 230 because the sex trafficking victims failed to prove the company actually knew about the abuse on its platform.

The Supreme Court held off on deciding whether to take the Reddit case while it resolved a pair of unrelated social media cases earlier in May. In those cases, the court left Section 230 intact, insulating Google and Twitter from liability for terrorist content on their platforms. 

It was a signal that the court is wary of weighing in on the complicated Section 230 statute, which laid the foundation for the modern internet. 

Social media companies have aggressively defended Section 230 as a necessary protection against a likely avalanche of multimillion-dollar lawsuits over vile and harmful online speech. But lawmakers in recent years have questioned whether Section 230 is overly broad and protects the internet platforms from accountability for the harms they enable.

The case is Jane Does No. 1-6 v. Reddit, 22-695.

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