Justices across the ideological spectrum said they were confused by the plaintiff’s case and concerned about undermining Congress’s intent

But justices across the ideological spectrum said they were confused by the arguments offered by the family’s lawyer and worried that the court could undermine an effort by Congress to provide immunity for the platforms decades ago, when lawmakers wanted to encourage the development of the internet.

Supreme Court Justice Elena Kagan said one could question why Congress provided such protections when passing Section 230 of the Communications Decency Act of 1996, which has been interpreted by courts to provide wide immunity from lawsuits when the sites post content from outside parties.

But she drew laughter when she wondered how far the Supreme Court should go in cutting back such protection.

"You know, these are not like the nine greatest experts on the internet,” Kagan said.

Read our live updates and analysis from the Gonzalez v. Google oral arguments

Kagan and Justice Brett M. Kavanaugh suggested a ruling on behalf of the Gonzalez family could unleash a wave of lawsuits. Kavanaugh did not seem persuaded when Deputy Solicitor General Malcolm L. Stewart, representing the Justice Department and siding in part with the plaintiffs, said few lawsuits "would have much likelihood of prevailing.”

“Isn’t it better … to keep it the way it is," Kavanaugh replied. "For us … to put the burden on Congress to change that and they can consider the implications and make these predictive judgments?”

Courts in the past have found the Section 230 law shields tech companies from culpability over the posts, photos and videos that people share on their services. Google argues that the law protects it from legal responsibility for the videos that its recommendation algorithms surface, and that such immunity is essential to tech companies’ ability to provide useful and safe content to their users.

The Gonzalez family’s lawyers say that applying Section 230 to algorithmic recommendations incentivizes promoting harmful content and denies victims an opportunity to seek redress when they can show those recommendations caused injuries or even death.

Justice Clarence Thomas, who has been a critic of big tech companies and the protections they received, said Tuesday that he was unsure how YouTube could be said to be aiding and abetting terrorism when its “neutral” algorithms worked the same way whether a viewer was seeking information on the Islamic State or how to make rice pilaf.

Chief Justice John G. Roberts Jr. wondered whether recommending a similar video to someone who has expressed interest in a subject is not the “21st Century” equivalent of a bookseller pointing a customer asking about sports books to the section of the store where they are kept.

Justice Sonia Sotomayor and Kagan told Eric Schnapper, a lawyer for the Gonzalez family, that his argument about algorithmic recommendations was very broad. Because algorithms are used to respond to virtually every search, Kagan said, Schnapper’s position might mean Section 230 really provides no protection at all.

Schnapper agreed algorithms are “ubiquitous” but noted the ones at issue involved YouTube recommending Islamic State videos.

Justice Ketanji Brown Jackson aggressively questioned lawyer Lisa S. Blatt, representing Google. Jackson suggested the original intent of Section 230 was to protect tech companies from liability but also to encourage them to take down offensive content.

But Blatt refused to make concessions. She held fast to her argument that Section 230 is broad, strong and crystal-clear — platforms are not liable when dealing with any kind of third-party content, regardless of how they do or don’t promote it to their users.

Companies must make choices about how to display content, she said, to help users find relevant information. To side with the argument of plaintiffs “defies the text” of the law, she told the justices, and “threatens today’s internet.”

Congress wrote Section 230 after a court found Prodigy Services liable for defamatory comments on its site. At the time, message boards reigned supreme and Americans were newly joining services such as CompuServe, Prodigy and AOL, allowing their unvetted posts to reach millions. The statutecontains what have been called the “26 words that created the internet.” Its key provision says no tech platform “shall be treated as the publisher or speaker of any information provided by another information content provider.”

YouTube parent company Google successfully quashed the Gonzalez family’s lawsuit in lower courts, arguing that Section 230 protects the company when it surfaces a video in the “Up Next” queue on YouTube, or when it ranks one link above another in search results.

But these and other wins came over the objections of some prominent judges who say lower courts have read the provision too broadly. “The Supreme Court should take up the proper interpretation of Section 230 and bring its wisdom and learning to bear on this complex and difficult topic,” wrote Judge Ronald M. Gould of the U.S. Court of Appeals for the 9th Circuit.

Fight over Florida, Texas social media laws is likely to land before Supreme Court

The case comes amid growing concern that the laws that govern the internet — many forged years before the invention of social media platforms like Facebook, YouTube, Twitter or TikTok — are ill equipped to oversee the modern web. Politicians from both parties are clamoring to introduce new digital rules after the U.S. government has taken a largely laissez-faire approach to tech regulation over the last three decades. But efforts to craft new laws have stalled in Congress, pushing courts and state legislatures to take up the mantle.

Now, the Supreme Court is slated to play an increasingly central role. After hearing the Google case on Tuesday, the justices on Wednesday will take up Twitter v. Taamneh, another case brought by the family of a terror-attack victim that alleges social media companies are responsible for allowing the Islamic State to use their platforms.

Justice Amy Coney Barrett said during oral arguments that the outcome of that case might be relevant to the Google lawsuit, and could dictate even whether the court has to settle the issues argued Tuesday

This is a developing story. It will be updated.