If politicians loudly and publicly insist their opponents are existential threats to democracy who seek to impose a dictatorship, they run the risk that people will take them seriously. Particularly unhinged or hate-filled followers may choose to lash out at what they’ve been warned are dangerous political enemies—even to the point of attempting to assassinate opposition leaders like Donald Trump. Twice. Trump is guilty of his own overheated rhetoric, of course. But so far, he’s been the one on the receiving end of those who take such language seriously. Well, Trump and regular people caught u…