Islamic State gunmen killed American college student Nohemi Gonzalez as she sat with friends in a Paris bistro in 2015, one of several attacks on a Friday night in the French capital that left 130 people dead.

Her family’s lawsuit claiming YouTube’s recommendations helped the Islamic State group’s recruitment is at the center of a closely watched Supreme Court case being argued Tuesday about how broadly a law written in 1996 shields tech companies from liability. The law, known as Section 230 of the Communications Decency Act, is credited with helping create today’s internet.

A related case, set for arguments Wednesday, involves a terrorist attack at a nightclub in Istanbul, Turkey, in 2017 that killed 39 people and prompted a suit against Twitter, Facebook and Google, which owns YouTube.

The tech industry is facing criticism from the left for not doing enough to remove harmful content from the internet and from the right for censoring conservative speech. Now, the high court is poised to take its first hard look at online legal protections.

A win for Gonzalez’s family could wreak havoc on the internet, say Google and its many allies. Yelp, Reddit, Microsoft, Craigslist, Twitter and Facebook are among the companies warning that searches for jobs, restaurants and merchandise could be restricted if those social media platforms had to worry about being sued over the recommendations they provide and their users want.