Putin is an open book. U.S. leaders have refused to read it.

Books featuring cover images of Russian President Vladimir Putin at the 11th Red Square Book Festival in Moscow on Wednesday. (Maxim Shipenkov/EPA-EFE/Shutterstock)

Recently, 20,000 people were evacuated from the center of the German city of Cologne because of a timely reminder from the past: three unexploded bombs dropped on the pulverized city during World War II. A thousand miles to the east, reverberations from explosions in Ukraine are part of Europe’s present. And of its foreseeable future, in part because of past misjudgments.