We learned from “Pizzagate” how dangerous fake new can be, when a man who believed the conspiracy theory brought a gun into a Washington pizza parlor and started shooting. But in Arizona, some TV stations seem to not have noticed, because they’re peddling a similar theory with dangerous credulity.

Emily Rooney was joined by Dan Kennedy of Northeastern University, Callie Crossley and Adam Reilly of WGBH News and former CNN White House Correspondent Dan Lothian to discuss.