New Delhi, April 27 -- When Cole Tomas Allen walked into the Washington Hilton on the evening of Saturday, 26 April, he was not there for the rubber chicken. The 31-year-old CalTech graduate from Torrance, California, who had spent months cataloguing his fury at the Trump administration on social media under the handle "Coldforce", had booked his room weeks in advance, arrived armed with a shotgun, a handgun, and knives, and, according to law enforcement officials, intended to cause "as much damage as he could."

What followed was a chaotic scene in the lobby of the hotel at approximately 8:30 p.m., as gunfire erupted near the security checkpoints, forcing the evacuation of President Donald Trump and several senior members of his administ...