On Friday, the Supreme Court signaled it would likely not be TikTok’s savior. If President-elect Donald Trump wants to play the role, he should do so within the confines of the law.

The wildly popular video-sharing app owned by Chinese tech giant ByteDance Ltd. faces a Jan. 19 deadline to divest or be banned from US app stores and servers. The company had hoped for a reprieve, claiming a ban would violate the rights of its 170 million US users to post their latest dance moves, recipe tips and bids for the Darwin Award. Trump’s lawyers filed a supporting brief arguing he should be given time to negotiate a solution after taking office. Instead, in questioning last week, most justices seemed inclined to believe Congress was within its rights to force a sale.

How much of a threat the app poses can be debated. National-security agencies warn the Chinese government could access user data to surveil, blackmail and intimidate Americans; could manipulate its opaque recommendation algorithm to promote propaganda or stir up social unrest; and could........

© Bloomberg