The court is hearing oral arguments on TikTok’s bid to block a law that would lead to its ban in the U.S. starting Jan. 19 if it isn’t sold by its Chinese owner.

The law that could ban TikTok is coming before the Supreme Court. The justices largely hold the app’s fate in their hands as they hear the case Friday.

The law—which prohibits U.S. app stores from hosting TikTok unless Chinese parent company ByteDance divests from it—is scheduled to take effect one day before Trump’s Jan. 2