WATCH: Advocates for greater social media protections for kids speak outside Meta trial

A federal court in California commenced a landmark trial on Tuesday, with a bipartisan coalition of 29 states accusing Meta, the parent company of Facebook and Instagram, of causing mental health harm to young users through its design. The trial, expected to span several weeks, began before District Judge Yvonne Gonzalez Rogers, who will ultimately rule.

Serving in an advisory capacity is an eight-member jury. Opening statements were delivered by Megan O'Neill, deputy California attorney general, who contended that Meta engineered its products to "hook users, hold them for as long as possible, extract data, and conceal the truth from the public, particularly effective for children."

The lawsuit, filed in 2023, claims Meta knowingly designed its apps to entice young users and collect data from children under 13, defying federal law. O'Neill stated, "Meta needed kids, and it needed to reassure those who cared about those kids that the kids are safe." Meta has adamantly denied the allegations, stating that the claims against the company are unsubstantiated and that it maintains robust protections for teenagers.

The states' demands are described as disproportionate, lacking evidence of any misleading claims, and the financial penalty requested is vastly higher than the company's market cap. The case's potential consequences could be severe for Meta, with fines as high as $1.4 trillion. However, the coalition is seeking $200 billion in fines.

Meta has already been fined $942 million in a separate New Mexico lawsuit, with additional penalties totaling $567 million. The case stems from a 2021 US Senate committee hearing where whistleblower Frances Haugen alleged that Meta knowingly promoted products detrimental to young users as the company pursued higher profits.