They say the first one to mention the Nazis automatically loses the argument. But anyone who reads a Hitler biography has to be struck by the similarities between the German dictator and a recent president. Among the similarities: They both claimed to be extraordinary, to have knowledge and abilities they didn’t possess. They raged against imaginary enemies. They blamed others for anything that went wrong, never themselves. They told lies by the truckload. They couldn’t be trusted. They ignored the law whenever it suited their purposes. They were psychologically insecure and viewed mild criticism as disloyalty. They came to power with the help of those who knew better. They convinced millions of their fellow citizens to follow them blindly, many to the point of their own destruction.

The final paragraph of Volker Ullrich’s two-volume biography of the mass murderer:

“We are not and cannot be done with confronting Adolf Hitler”, wrote the Catholic author Reinhold Schneider in 1946. “In a certain sense, we will be bound to him for all eternity.” Schneider’s words remain pertinent today. Hitler will remain a cautionary example for all time. If his life and career teaches us anything, it is how quickly democracy can be prized from its hinges when political institutions fail and civilizing forces in society are too weak to combat the lure of authoritarianism; how thin the mantle separating civilization and barbarism actually is; and what human beings are capable of when the rule of law and ethical norms are suspended and some people are granted unlimited power over the lives of others.