A social media giant’s challenge to a new California law on content moderation raises a simple question: What types of speech are hateful?

It’s a question whose answer holds First Amendment considerations that could soon draw in the Supreme Court, legal experts say.

X, formerly known as Twitter, this month filed a federal lawsuit arguing that California Assembly Bill 587 infringes on free speech. The law requires media companies to post terms of service about how they handle certain content and inform the government about how they are moderating certain content.

The lawsuit claims the legislation “impermissibly interferes with the constitutionally protected editorial judgments of companies such as X Corp.”

“There’s a strong argument that this kind of disclosure requirement for speech policies interferes with editorial judgment too much,” said Rebecca Tushnet, a professor at Harvard Law School.

Kyle Langvardt, a law professor at the University of Nebraska-Lincoln, said X’s challenge is a “serious claim.”

He said the disclosures required under the California law force media companies to define certain speech, such as harassment. The companies also must report how they’re handling harassment and can be subject to a fine if they omit or misrepresent anything.

“The power to seek these fines could, potentially, empower prosecutors to pressure platforms to change their content enforcement policies,” Mr. Langvardt said.

A spokesperson for the California attorney general’s office said it is eager to defend the law.

“We look forward to fighting for this commonsense law in court, which requires social media companies with annual gross revenues of at least $100 million to publicly disclose information about their content-moderation policies,” the spokesperson said.

Texas, Florida and New York also have enacted various disclosure requirements.

New York had a Hateful Conduct Law requiring social media companies to allow users to file complaints over hate speech and requiring the companies to implement a policy on how to handle hate speech.

A federal court blocked the law from being enforced this year, reasoning that its requirements infringed on free speech rights by penalizing hate speech, which is protected by the First Amendment.

In Texas, lawmakers passed a law in 2021 prohibiting social media companies from removing and moderating content that some might find offensive or hateful. It also required the companies to disclose certain business practices such as the use of algorithms.

A federal court in Texas blocked parts of the law from taking effect. The 5th U.S. Circuit Court of Appeals reversed that ruling but kept the injunction in place, pending appeal.

And in Florida, lawmakers enacted in 2021 a law that placed a fine of $25,000 to $250,000 per day on large social media companies that de-platform political candidates.

The U.S. District Court and 11th U.S. Circuit Court of Appeals blocked the law from taking effect on First Amendment concerns.

The Texas and Florida challenges are pending before the Supreme Court, and the justices are scheduled to consider taking them up during their conference on Sept. 26, which is not open to the public.

It would take four justices to vote in favor of hearing the disputes for oral arguments to be heard.

The Justice Department said the conflicting rulings from the 5th and 11th Circuits suggest the high court should grant review in the disputes and rule whether the laws interfere with the companies’ and users’ First Amendment rights.

“The platforms’ content-moderation activities are protected by the First Amendment, and the content-moderation and individualized-explanation requirements impermissibly burden those protected activities,” Solicitor General Elizabeth Prelogar said in the federal government’s filing.

NetChoice, an advocacy group that aims to keep the internet free, is leading the challenge in both high court petitions.

The group said in a press release this month that California’s requirements for social media companies are an “aggressive” censorship attempt “disguised as a transparency law.”

“The First Amendment prohibits the government from regulating lawful speech — directly or indirectly. States cannot avoid this prohibition by rebranding censorship as ‘transparency’ requirements,” said Chris Marchese, director of litigation for NetChoice.

The case, X Corp. v. Bonta, was assigned to U.S. District Judge William B. Shubb, a George W. Bush appointee for the Eastern District of California.