The U.S. Supreme Court on Tuesday issued a ruling blocking a Texas law aimed at preventing big social media services from “censoring” users or content based on viewpoint.

The court ruled 5-4 to block the law, which is pending a challenge before a federal appeals about whether it is constitutional. The court did not provide a reason for why it upheld a lower court’s injunction preventing the Texas law from taking effect pending appeal.

The Supreme Court was ruling on an emergency application filed by two tech industry groups, representing companies including Meta, Google, TikTok and Twitter, which had claimed that the Texas law “would compel platforms to disseminate all sorts of objectionable viewpoints,” including “neo-Nazi or KKK screeds denying or supporting the Holocaust.”

The Texas law would make it illegal for large social networks to “block, ban, remove, de-platform, demonetize, de-boost, restrict, deny equal access or visibility to, or otherwise discriminate against expression.”

Known as HB 20, the Texas law applies to social media platforms with more than 50 million active monthly users, a group that includes Facebook, Twitter, Instagram, YouTube and Snapchat. The legislation was passed in September 2021, but a lower court granted a preliminary injunction preventing it from taking effect.

In December, a judge in the U.S. District Court for the Western District of Texas issued a preliminary injunction blocking the law, citing the First Amendment. “Social media companies have a First Amendment right to moderate content disseminated on their platforms,” Judge Robert Pitman wrote in the decision.

In a dissenting opinion on Tuesday’s Supreme Court ruling, Justice Samuel Alito Jr. wrote that the preliminary injunction “was itself a significant intrusion on state sovereignty” and that Texas “should not be required to seek preclearance from the federal courts before its laws go into effect.” He also wrote that “it is not at all obvious how our existing precedents, which predate the age of the internet, should apply to large social media companies.”

“Social media platforms have transformed the way people communicate with each other and obtain news,” Justice Alito wrote. “At issue is a groundbreaking Texas law that addresses the power of dominant social media corporations to shape public discussion of the important issues of the day.”

Texas Attorney General Ken Paxton, writing in response to the emergency application to the Supreme Court, had argued that social media giants “are the 21st-century descendants of telegraph and telephone companies: that is, traditional common carriers” — and as such, the First Amendment doesn’t prevent the government from “keeping the platforms’ communications pathways open through common-carriage requirements.”

Conservatives have long asserted that internet platforms somehow harbor an anti-conservative bias — something that Elon Musk, whose $44 billion bid for Twitter is pending, agrees with. One of the key triggers for Texas’ HB 20 legislation was the ban imposed on Donald Trump by YouTube, Facebook, Twitter and others after he praised the rioters who attacked the U.S. Capitol on Jan. 6, 2021, seeking to overturn the 2020 presidential election.

Last week, a federal appeals court ruled that a Florida law similar to Texas’ HB 20 was unconstitutional because social media platforms’ content-moderation activities “constitute ‘speech’ within the meaning of the First Amendment.” The Florida law was designed to prohibit social media companies from banning politicians, political candidates or “journalistic enterprises.”