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 lawyer for TikTok and its Chinese parent company ByteDance offered a warning during Supreme Court arguments over a law that would compel the sale of the short-video app or ban it in the United States: If Congress could do this to TikTok,

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.