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,

The Supreme Court seemed inclined on Friday to uphold a law that would force a sale or ban the popular short-video app TikTok in the United States by Jan. 19, with the justices focusing on the national security concerns about China that prompted the crackdown.

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.