The U.S. Supreme Court refused to rescue TikTok on Friday from a law that required the popular short-video app to be sold by its Chinese parent company ByteDance or banned on Sunday in the United States on national security grounds – a major blow to a platform used by nearly half of all Americans.

The justices unanimously ruled that the law, passed by an overwhelming bipartisan majority in Congress last year and signed by Democratic President Joe Biden, did not violate the U.S. Constitution’s First Amendment protection against government abridgment of free speech. The justices affirmed a lower court’s decision that had upheld the measure after it was challenged by TikTok, ByteDance and some of the app’s users.

“There is no doubt that, for more than 170 million Americans, TikTok offers a distinctive and expansive outlet for expression, means of engagement, and source of community. But Congress has determined that divestiture is necessary to address its well-supported national security concerns regarding TikTok’s data collection practices and relationship with a foreign adversary,” the court said in the unsigned opinion.

The court added that “we conclude that the challenged provisions do not violate petitioners’ First Amendment rights.”