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 platform with nearly 170 million American users is challenging a law that would see it banned in the US in a matter of days.