The Supreme Court on Friday was divided over the constitutionality of a federal law that would require social-media giant TikTok to shut down in the United States unless its Chinese parent company can sell it by Jan.

The social media app TikTok is facing a potential ban in the United States as lawmakers and cybersecurity experts continue to raise concerns about the app’s security and its potential influence by the Chinese government.

Lawyers for TikTok will argue that banning the app will violate the free speech of 170 million American users. The Justice Department will contend that the app is a national security risk.