Florida’s social media law threatens “severe harm” to social media companies as well as their users, the Interactive Advertising Bureau and other organizations are telling the Supreme Court.

The bill is “designed to force a sea change in how platforms operate, against the will of both the platforms and the users who have come to rely upon them, and all because Florida does not like the content of the messages that platforms are serving to their users,” the organizations say in a friend-of-the-court brief filed this week with the Supreme Court.

Florida’s law, passed last year, subjects social media companies to fines of $250,000 per day for “deplatforming” candidates for statewide office, and $25,000 per day for other offices. (The bill defines deplatforming as suspending for more than 14 days or banning.)

The measure (SB 7072) also prohibits large social-media platforms from “censoring” journalistic enterprises based on content. Other provisions require platforms to disclose their policies regarding acceptable content.

The Florida bill, like a similar law in Texas, was driven by Republicans’ belief that tech companies are biased against conservatives.

“Silicon Valley is acting as a council of censors,” Florida’s Republican governor Ron DeSantis said when he signed the bill, adding that tech companies “use shadow banning and secret algorithms to shape debates and control the flow of information.”

The tech industry groups NetChoice and Computer & Communications Industry Association challenged the law in court, and were mostly successful. The 11th Circuit Court of Appeals blocked enforcement of the bulk of the bill, on the grounds that tech companies have the First Amendment right to exercise editorial control over content on their platforms. But the appellate court also allowed the state to enforce some provisions requiring companies to disclose their policies.

Florida Attorney General Ashley Moody recently urged the Supreme Court to review the portion of the ruling that blocked enforcement. She argued in papers filed in September that states like Florida have the right to “protect their citizens’ access to information” by requiring tech platforms to carry users’ speech.

For their part, NetChoice and Computer & Communications Industry Association are asking the Supreme Court to review the portion of the law that requires companies to disclose their content moderation policies procedures.

This week, the Interactive Advertising Bureau was part of a broad coalition of groups — including the Chamber of Progress, Global Project Against Hate and Extremism and Information Technology & Innovation Foundation — to side with NetChoice in friend-of-the-court brief.

The organizations say the reason tech companies suppress posts is to prevent their services from being overrun with problematic material — including spam, “vile, graphic videos and images,” and “reprehensible speech — such as the glorification of terrorist attacks and the dissemination of pro-Nazi views.”

“S.B. 7072 would effectively gut platforms’ efforts at content moderation, to the ultimate detriment of their users,” the groups write.

They add that the disclosure mandates — which include requirements to provide information about algorithms that flag objectionable content — “will have disastrous consequences for keeping spam, terrorist promotion, and other distasteful content off platforms.”

Mandating disclosure of algorithms “would inevitably enable bad actors, spammers, and scammers to better circumvent content moderation techniques,” the groups write.

Florida’s social media “censorship” law is “designed to force a sea change in how platforms operate, against the will of both the platforms and the users who have come to rely upon them, and all because Florida does not like the content of the messages that platforms are serving to their users,” the IAB and others tell the Supreme Court.