American lawmakers have tried for years to ban TikTok, concerned that the video app’s links to China pose a national security risk. Sapna Maheshwari, a technology reporter for The Times, explains the behind-the-scenes push to rein in TikTok and discusses what a ban could mean for the app’s 170 million users in the United States. Guest: Sapna Maheshwari, who covers TikTok, technology and emerging media companies for The New York Times.