resident Barak Obama didn't intend to make the Battle of Yarmuk (636 A.D.) a 2015 news item. However, his bizarrely incomplete sketch of the Crusades, delivered last week at a national prayer breakfast, did just that. The president's media defenders contend he intended to make a justifiable point: Throughout history, people have corrupted religious faith to self-serving, murderous ends. That, however, is an oft-repeated truth -- something everyone already knows. But our president, while repeating something we already know, equated medieval Christian crusaders with 21st-century Islamic State terrorists. See, man? They both committed atrocities. Obama started solid, dubbing the Islamic...