On Dec. 4, a 28-year-old North Carolina man bearing a handgun and a military-style rifle stormed a Washington, D.C., pizza joint called Comet Ping-Pong, determined to “self-investigate” rumors that the restaurant was the center of a child sex-slave ring with connections to the Clinton campaign. Edgar M. Welch, of Salisbury, N.C., who fired his weapon inside the restaurant but injured no one, later admitted “the intel on this wasn’t 100%.”