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.

Congress labeled the app’s Chinese ownership a national security risk and passed a law that would ban the social media platform unless it was sold. TikTok and creators say that violates their free speech rights.

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