When gun control activists with Everytown for Gun Safety and Students Demand Action held a rally at the Kentucky state capitol in February to push for new restrictions on the right to keep and bear arms, one of the speakers captivated the small crowd of anti-gunners with his moving story about surviving a mass shooting at his Pennsylvania high school. As it turns out, however, what Calvin Polachek told the crowd was an outright lie. He invented the school shooting and his self-proclaimed trauma, and now Everytown is scrambling to distance themselves from the man they put in front of...