A TikTok ban might be one step closer to reality even if there are still some lingering doubts about whether a federal law will really go into effect on January 19.

The justices are expected to rule quickly in the case, which pits national security concerns about China against the First Amendment’s protection of free speech.

The court heard 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.