More than four dozen former foreign and national security officials for the U.S. government called on Biden in a letter Friday to drop out of the presidential race. "We write as former U.S. officials who have strongly supported your presidency and your initiatives to strengthen U.S. foreign and national security policy," they wrote. "We have welcomed the measures you have taken to promote U.S. alliances in Europe, Asia, and the Americas; to manage relations with great powers; and to address global issues such as climate change. These initiatives have been built on your decades-long record of support for responsible U.S....