Open this photo in gallery: Signs have gone up at U.S. national parks telling visitors to report 'negative' information about America.BRENDAN SMIALOWSKI/AFP/Getty Images We are living through history. Right now, this week. We are being dragged, kicking and screaming, through it. They will study this period one day: Iran, Israel, Gaza, Ukraine, Russia. Donald Trump. Fortunately, there is a wealth of documentation about these matters, delivered daily (even if some accounts are more credible than others). But what happens when a country deliberately sets out to erase its history? The unpleasant bits, in particular. We saw this in 20th-century totalitarian...