Dihan Rahman pleaded guilty possessing bomb-making materials last week. He was targeting the high school prom and plotting a massive Valentine’s Day massacre. He pleaded guilty on the second day of his trial. Rahman admitted possessing terrorist material, including guides on how to build bombs, after an investigation by Counter Terrorism Policing London. Authorities also found violent Islamist material on his phone. According to Sky News, Dihan was the the administrator of a far-right social media group in the first known case of extremists finding “common ground” over their hatred of Jews. He posted one photo online of himself giving...