With no radical footprint, what drove suspect to try and assassinate Trump?

Law enforcement surrounds the Washington Hilton Hotel where shots were fired near the White House Correspondents' Association Dinner featuring President Donald Trump in Washington, D.C., on April 25. Andrew Leyden/ hide caption toggle caption Andrew Leyden/ Monday's arraignment of 31-year old Cole Tomas Allen, a California man who is charged with attempting to assassinate President Trump over the weekend, opened legal proceedings that many extremism experts will be watching closely. Allen, a high school tutor with a background in mechanical engineering and computer science, allegedly attempted to storm the annual White House Correspondents Association Dinner on Saturday night, where Trump and other high-level administration officials were gathered with the Washington press corps. He was stopped by federal law enforcement officers before getting close to his presumed targets. According to a White House official , Allen's sister told the Secret Service and local law enforcement that her brother was known to make "radical" statements. The official was not authorized to speak publicly and NPR has not confirmed this with Allen's family members. But this characterization has puzzled some experts who track extremism, who say that it does not align with writings and social media activity that are believed to link to the defendant. …