The Supreme Court on Friday unanimously upheld the federal law banning TikTok beginning Sunday unless it's sold by its China-based parent company, holding that the risk to national security posed by its ties to China overcomes concerns about limiting speech by the app or its 170 million users in the United States. A sale does not appear imminent and, although experts have said the app will not disappear from existing users' phones once the law takes effect on Jan. 19, new users won't be able to download it and updates won't be available. That will eventually render the app unworkable, the Justice Department has said in court filings.