A recent RAND Corporation paper, “Avoiding a Long War,” has caused a stir in the policy community, even inspiring New York Times columnist Ross Douthat to cite it approvingly. The authors of the paper, Samuel Charap and Miranda Priebe, argue that a long war in Ukraine is not in the U.S. interest and, thus, that Washington’s policy should focus on avoiding it. At first glance, the argument seems perfectly plausible. Who would want a long war if a short one is possible? Who could possibly prefer more death and destruction to less death and destruction? (Well, Adolf Hitler and Vladimir...