Hitler's greatest mistake in WWII was likely his decision to invade the Soviet Union in June 1941, an operation known as Operation Barbarossa. This decision had several detrimental consequences:
- Overextension of German resources: The vastness of the Soviet Union stretched German supply lines and forced them to fight on multiple fronts, diverting resources from other theaters of war.
- Underestimation of Soviet strength: Hitler and his generals underestimated the resilience and determination of the Soviet people and their military, leading to a protracted and bloody conflict.
- Opening a new front: The invasion of the Soviet Union opened a new front for Germany, forcing them to contend with a powerful and resourceful enemy.
- Failure to secure a quick victory: Hitler's initial aim was to achieve a swift victory in the east, but the campaign dragged on for years, draining German resources and morale.
While other mistakes, such as the declaration of war on the United States, the failure to secure British surrender, and the persecution of minorities, contributed to Germany's defeat, the invasion of the Soviet Union arguably had the most significant and lasting impact on the course of the war. This decision ultimately led to the deaths of millions of soldiers and civilians, the devastation of Eastern Europe, and the eventual collapse of the Nazi regime.