In his court-martial, Teixeira faces charges of disobeying orders and obstructing justice. At a hearing last year, military prosecutors said a court-martial is appropriate given that obeying orders is the "absolute core" of the military. But Teixeira's lawyers argued that further action would amount to prosecuting him twice for the same offense.
The court-martial panel is convening at Hanscom Air Force Base in Massachusetts.
The leaks exposed to the world unvarnished secret assessments of Russia's war in Ukraine, including information about troop movements in Ukraine, and the provision of supplies and equipment to Ukrainian troops. Teixeira also admitted posting information about a U.S. adversary's plans to harm U.S. forces serving overseas.