During a lengthy hearing Friday, the U.S. Supreme Court appeared to be leaning in favor of upholding a law forcing the popular social media app TikTok to be divested from its Chinese parent company or else shut down in the United States by Jan. 19.

The justices spent more than 2½ hours hearing Friday's high-stakes First Amendment case, TikTok v. Garland, which threatens to unplug a video-sharing platform used by 170 million Americans over concerns about national security. TikTok, and a group of content creators on the platform, say the law is a blatant violation of free speech and have urged the court to step in before the platform goes dark in nine days.