Texas Governor Greg Abbott has signed a bill regulating how social media companies moderate content.

The new law, passed as HB 20 in early September, controversially prohibits banning (or demonetizing or otherwise restricting) content based on “the viewpoint of the user or another person,” whether or not that viewpoint is expressed on the social media platform itself.

HB 20 also requires social media services to disclose how they promote and moderate content and mandates transparency reports similar to those produced by Facebook, Google, and other major web companies. If platforms are notified of illegal content, the law requires them to evaluate it within 48 hours, a policy that mirrors at least one proposal in US Congress. (Unlike Congress, however, a state legislative body can’t override Section 230 of the Communications Decency Act — which governs much moderation of illegal content online.)

Companies that break the rules could face a civil lawsuit or action from the attorney general. The law applies to web services with more than 50 million active users that let people “communicate with other users for the primary purpose of posting information, comments, messages, or images,” not including internet service providers and news or entertainment sites.

The law also includes a section specifically aimed at email platforms — making it unlawful to “intentionally impede the transmission of another person ’s electronic mail message based on the content of the message” unless the company believes it contains malicious code, obscenity, illegal content, or violations of an existing Texas anti-spam law.

The Texas law is one of several Republican efforts to scare web companies away from removing objectionable but lawful content, a fight conservative politicians have framed as an anti-censorship battle against companies that are akin to phone companies or other communications utilities. It follows a similar Florida law covering social media, although it doesn’t include some of that rule’s more distinctive provisions, like protections for political candidates and an exemption for companies that own a theme park.

The rule’s future, however, is uncertain. It’s likely to face legal challenges from critics, and unlike the recent Texas abortion ban, it’s not tailored to evade judicial scrutiny. A judge blocked Florida’s social media law in June, saying it “compels providers to host speech that violates their standards.”

NetChoice, one of the plaintiffs in that Florida lawsuit, released a statement condemning the bill. “HB 20 has the same First Amendment flaws as the Florida law that a federal court blocked this summer. The same outcome will almost certainly occur in Texas,” said NetChoice president Steve DelBianco in a statement. So far, however, it hasn’t committed to a similar lawsuit there.