Perhaps the most appalling of these legacies is the way Adolph Hitler and his regime consciously drew on U.S. actions toward Native Americans as a model for their murderous campaign in Eastern Europe during World War II. This is a connection explored by recent historians of Nazi Germany and detailed most comprehensively in Carroll Kakel’s “The American West and the Nazi East.” (For a related account of how American immigration, segregation and eugenics policies influenced the Nazis, see James Whitman’s fascinating “Hitler’s American Model.”)

Hitler’s overriding strategic goal in launching World War II was stretching Germany’s borders eastward to encompass most of Europe. This quest for Lebensraum, or living space, to the east was his central preoccupation. He envisioned a vast German empire extending through the Baltics, Poland, Ukraine, Belarus and Russia — all the way to Europe’s end at the Ural Mountains. This empire would be gradually cleared of its former inhabitants and populated instead by rugged, self-reliant German farmers growing food to feed a great continental power.

World War II, then, was above all a war of colonial expansion. At a time when European countries still ruled much of the world, justifying such rule by claims of racial superiority and using brutal methods to extract wealth and crush dissent, Hitler had many models to look to for inspiration. Belgium, for instance, killed or worked to death an estimated 10 million people during its four decades ruling Congo.

His focus, however, was not on overseas colonies, which Germany had never acquired to the same extent as other powers, but on a contiguous, land-based empire annexed to the German homeland itself. As Hitler said, “Our colonial territory is in the east.” His was a vision of what historians call “settler colonialism,” in which an area’s original inhabitants may be exploited temporarily but are ultimately replaced by the conquering country’s own people.