The Supreme Court seemed likely to uphold a law that would ban TikTok in the United States beginning Jan. 19 unless the popular social media program is sold by its China-based parent company. Hearing arguments in a momentous clash of free speech and national security concerns,

A majority of the justices appeared more concerned about the national security implications of the popular app’s Chinese ownership than about the restrictions on free speech the law would impose.

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.