To evidence the shifting shape of the social media landscape, Zuckerberg pointed to a 2018 decision by the company to highlight content from users’ real friends and family rather than other user-generated content, noting that this effort flopped amid users’ growing demands for content from sources outside of their real-world networks.

Meta’s legal team has argued that the relevant market in the case should be far more broad, as Meta platforms compete against other social giants like TikTok, YouTube, and X. 

Meta’s defense is being led by Mark Hansen, a partner at Kellogg, Hansen, Todd, Figel & Frederick. Hansen, in his opening remarks on Monday, said the FTC’s arguments are “at war with the facts and at war with the law.”

Even if it prevails, the FTC must prove that splitting up Meta would meaningfully boost competition.

The case will be decided by U.S. District Judge James Boasberg. The culmination of a crackdown on Big Tech undertaken during Donald Trump’s first presidential administration, the trial is expected to stretch on for up to two months.