A U.S. judge has ordered the Trump administration to preserve messages from a Signal group chat used by top national security officials to discuss plans for an attack on Yemen's Houthis, after it was revealed that a journalist was accidentally included in the group. Josef Gregory Mahoney, professor of politics at East China Normal University, says the U.S. government's use of a platform run by a private company raises not only security concerns but also issues related to government recordkeeping.