As we wait to see what shape President Donald Trump’s foreign policies will take, debate over former President Barack Obama’s legacy continues. Did Obama successfully end the war in Iraq, or did he help create the Islamic State by withdrawing U.S. troops too soon? Was it prudence or poor judgment that kept Obama from intervening in Syria’s civil war? The Obama era will have a deep impact on policy debates for years to come, serving as a template that will shape how decision-makers think about the use of military force. Getting the assessment right is crucial. Unfortunately, many seem to view...