U.S. soldiers at a joint military exercise against the Islamic State group in Syria on Sept. 7, 2022. (Delil Souleiman/AFP via Getty Images) A tranche of what appears to be classified U.S. intelligence material was posted anonymously on the social media platform Discord over the last three months in the latest leak of highly guarded national secrets. The documents, all photographs of printouts, pertain to a host of sensitive American national security matters, including the ongoing U.S.-led coalition campaign to defeat the Islamic State group, the disposition of U.S allies in the Middle East and Europe with respect to Russia,…