The U.S. Supreme Court justices on Friday expressed skepticism about a challenge from TikTok and its Chinese parent company ByteDance against a law signed by President Joe Biden, which would force the sale or ban of the popular short-video app by Jan. 19 in the United States.

Some of the justices seemed to acknowledge Congress' national security concerns over TikTok, given its ownership by what lawmakers deemed a foreign adversary.

Here's what could happen on Jan. 19.