Since the 2016 presidential election, liberal educators across the fruited plain have gone slap crazy. I wrote about these phenomena in my new book, “The Deplorables’ Guide to Making America Great Again.” Some teachers have even turned their classrooms into breeding grounds for anti-Trump propaganda – going so far as to portray the commander-in-chief as a modern-day Adolf Hitler. And I lost count of the number of educators who refused to broadcast the inauguration ceremony over fears that some fragile snowflake might take offense. But what happened in Dallas is yet another example of how our public schools have been...