An American soldier stationed at Fort Polk in Louisiana was arrested last week after he told users on the popular messaging platform Discord that he planned to conduct a mass shooting at a synagogue. Jakob Marcoulier, 22, was arrested on Thursday and charged with transmitting a threat in interstate commerce after the FBI’s National Threat Operations Center received a tip in February that he had made threats toward synagogues, according to the US attorney’s office for the Western District of Louisiana. According to court documents, the FBI obtained audio from Discord in which Marcoulier allegedly said, “After this deployment if...