Aaron “Jay” Danielson was shot and killed Saturday in downtown Portland, Ore., where he was participating in a vehicle caravan to show support for President Trump. No one has been charged, but the Oregonian newspaper reports police are investigating 48-year-old Michael Forest Reinoehl, who described himself on Facebook as “100% Antifa.” Not long after Danielson was killed, a video was posted to the internet of a woman in Portland shouting into a bullhorn: “Our community can hold its own without the police. . . . I am not sorry a f— fascist died tonight!” That elicited cheers and applause from...