Final answer:
Many historians believe that FDR and Churchill made a mistake by insisting on unconditional surrender in WWII, but others argue it was necessary to prevent future aggression.
Step-by-step explanation:
Many historians believe that FDR and Churchill made a mistake by insisting on "unconditional surrender" in World War II because they argue that it prolonged the war and caused unnecessary human suffering. They believe that a negotiated settlement could have been reached earlier, avoiding the destruction caused by the bombings of Hiroshima and Nagasaki. However, others argue that unconditional surrender was necessary to prevent future aggression and ensure lasting peace. By demanding that the Axis powers surrender without any conditions, it sent a strong message that aggression would not be tolerated.