In a ruling that will ripple across digital media, the U.S. Supreme Court on Sunday upheld a law that effectively places TikTok under a nationwide ban. The wildly popular social media platform used by about half the country would be shut down if President-elect Donald Trump doesn't throw an 11th-hour lifeline, saying he can strike a deal to save the app.

In a ruling issued Friday, the judge concluded that the law did not directly conflict with the First Amendment because it targeted TikTok's ownership of a company allegedly controlled by China, not its free speech rights. The law directs the app's parent company, ByteDance, to sell TikTok by January 19. Otherwise, web hosting services and mobile app stores will be prohibited from carrying TikTok.

With more than 150 million monthly active users in the United States, the app has become deeply integrated into American culture. It is by far the leading video sharing app in the country when it comes to grabbing and retaining users' attention. The ban will disrupt the income streams of hundreds of thousands of creators. Meta and Google have begun to fill the short-video void left by TikTok, and these companies are expected to see significant growth in their advertising businesses.

Prior to the ruling, there were rumors that Trump would issue an executive order the day after the ban took effect to suspend the shutdown for up to 90 days, but it was unclear what legal avenues he could take. Last month, he filed an amicus brief seeking to delay the law, saying he could find a solution that balanced national security and First Amendment considerations brought about by the ban. Overall, he expressed support for TikTok in opposing the law, which he said "exerted extraordinary power" to effectively shut down a wildly popular platform that was critical to free speech.

Government officials and lawmakers have repeatedly said TikTok poses a national security threat because of its relationship with ByteDance. So far, they have not provided any evidence that the company provided user data to the Chinese government or that it was directed to influence what users saw on the platform.

TikTok opposed the ban in part because of its function as a news source. It said its algorithms that recommend or block certain news items to users constitute free speech protected by the First Amendment.

The company also argued that the government cannot determine ownership of websites, newspapers and online platforms, as well as other privately created forums for speech.

The administration responded by saying the law banning TikTok was necessary to prevent China from spreading misinformation and curbing the collection of Americans’ private information.

Justice Brett Kavanaugh emphasized during oral arguments earlier this month that "Congress and the President are concerned" that "China is obtaining information about millions of Americans, tens of millions of Americans, including teenagers, people in their 20s, year old person.”