“Sometimes rhetoric has consequences,” Mr. Massie wrote. “If you spend days, weeks, months, years telling people they are under threat, that their country has been stolen from them, that they have been betrayed and sold down the river, that their birthright has been pilfered, that their problem is they’re too slow to realize any of this is happening, that their problem is they’re not sufficiently mad as hell, then at some point, in some place, something or someone is going to snap. And then something terrible is going to happen.”