Nohemi Gonzalez, a 23-year-old California college student, was studying abroad in Paris in November 2015 when she was among the 130 people killed in a coordinated series of terrorist attacks throughout the city.

The next year, her father sued Google and other technology companies. He accused the firms of spreading content that radicalized users into becoming terrorists, and said they were therefore legally responsible for the harm inflicted on Gonzalez’s family. Her mother, stepfather and brothers eventually joined the lawsuit, too.

Their claims will be heard in the U.S. Supreme Court on Tuesday. And their lawsuit, with Google now the exclusive defendant, could have potentially seismic ramifications for the social media platforms that have become conduits of communication, commerce and culture for billions of people.