Jens Asbjørn Bøgen
It’s hard to pinpoint a single factor as responsible for the Nazis’ defeat, but all of them played a major role in the eventual downfall of Nazi Germany.
Adolf Hitler’s rise and fall was driven as much by catastrophic decision-making as by the military power he briefly commanded.
While the Third Reich’s collapse had many causes—economic limits, Allied resilience, internal Nazi brutality and incompetence—historians often point to several pivotal choices that turned early advantages into irreversible defeat.
Below are five of Hitler’s biggest strategic mistakes, each one compounding the next and together sealing Nazi Germany’s fate.
1. The halt order at Dunkirk
In May 1940, Germany’s lightning campaign in the West trapped large parts of the British Expeditionary Force (BEF) and French armies near the port of Dunkirk. German panzer units had raced to the Channel and were positioned to annihilate the pocket.
Then, on 24 May, Hitler approved a sudden halt to armored advances, leaving the encircled Allies a narrow lifeline to the sea.
The pause—still debated in detail—was justified by German commanders as a way to rest tanks, avoid difficult marshy terrain, and let the Luftwaffe finish the job from the air.
According to The National Interest, many historians believe that Hitler also wanted to preserve armor for the next phase of the French campaign and had faith that air power could destroy the trapped forces.
But the Luftwaffe failed to prevent evacuation, and the delay gave Britain time to launch Operation Dynamo.
The result was one of the most consequential escapes in modern warfare: roughly 338,000 Allied troops were evacuated to Britain, including the core of the BEF.
Instead of eliminating Britain’s best-trained field army and potentially forcing London toward a negotiated peace, Hitler allowed those soldiers to live to fight again.
Dunkirk didn’t “win” the war for the Allies, but it kept Britain in the war—and a still-standing Britain became the launchpad for everything that followed: the air war, North Africa, and eventually D-Day.
2. The Blitz: bombing London and British cities
After failing to destroy the Royal Air Force (RAF) in the Battle of Britain, Hitler shifted the Luftwaffe’s focus from airfields, radar sites, and aircraft factories to mass bombing of London and other cities beginning 7 September 1940.
This decision began the Blitz—an eight-month campaign meant to break British morale and cripple industry.
Strategically, the shift was a gift to Britain. RAF Fighter Command was under severe stress in late August 1940; continuing systematic attacks on its infrastructure might have pushed it to the brink.
Instead, the new emphasis on cities reduced pressure on airbases and gave the RAF time to repair runways, reorganize squadrons, and rotate exhausted pilots.
The Blitz also failed on its own terms. While it inflicted terrible civilian casualties and destruction, British wartime production did not collapse; output, including aircraft production, recovered and even increased during the bombing period.
The raids hardened British resolve rather than shattering it, and Germany’s inability to secure air superiority meant any invasion of Britain (Operation Sea Lion) became fantasy.
In short: the Blitz turned a contest Hitler might still have influenced—air superiority over southern England—into a strategic dead end that strengthened the enemy he needed to neutralize first.
3. Attacking the Soviet Union (Operation Barbarossa)
On 22 June 1941, Hitler launched Operation Barbarossa, the invasion of the Soviet Union. It was the largest land invasion in history, driven by ideology (anti-Bolshevism, racial empire-building) and a belief that the USSR would collapse quickly.
The gamble failed—and the Eastern Front became the central furnace that consumed the Third Reich.
According to the Imperial War Museums, the German plan assumed a short campaign ending before winter but underestimated Soviet manpower, industrial depth, and capacity to relocate factories eastward.
Logistics were overstretched across vast distances; German forces relied heavily on horses and insufficient motor transport, while supply lines grew longer and more fragile.
Once the blitzkrieg tempo slowed, the Red Army absorbed losses, regrouped, and counterattacked, aided by harsh weather and German equipment failures.
Barbarossa’s failure was a turning point, according to Encyclopaedia Britannica: Germany became stuck in a long, brutal war of attrition it could not sustain while simultaneously still fighting Britain and later the United States.
Most importantly, the invasion created an enemy with the scale to destroy Nazi Germany. By 1943–45, the Soviets were not merely surviving—they were pushing west with overwhelming force.
4. Declaring war on the United States
After Japan attacked Pearl Harbor on 7 December 1941, Hitler was not obligated by treaty to declare war on the U.S. Yet on 11 December he did exactly that.
Hitler believed war with America was inevitable, assumed the U.S. was militarily weak and politically divided, and hoped that unrestricted U-boat warfare would starve Britain before American power could fully mobilize.
Instead, his declaration united U.S. public opinion behind a two-theater war and removed any remaining political obstacles for Roosevelt to prioritize defeating Germany first.
According to the National WWII Museum, economically, this was fatal. The United States possessed industrial capacity far beyond Germany’s. Once fully engaged, it became the “arsenal of democracy,” supplying Britain and the USSR with weapons, vehicles, fuel, and food on a scale Germany could never match.
Hitler had turned a powerful potential adversary into an active, committed one—while already bogged down in the Soviet Union.
Even if the U.S. would eventually have entered the European war, Hitler’s timing gave the Allies unity earlier and on better terms.
5. Believing D-Day was a deception
According to the Imperial War Museums, by 1944 Hitler knew a cross-Channel invasion was coming, but he and much of the German high command were convinced the main blow would land at Pas-de-Calais, not Normandy.
Allied deception operations (especially Operation Fortitude) reinforced this belief using fake armies, double agents, and misleading radio traffic.
When the Allies landed in Normandy on 6 June 1944, Hitler treated it as a feint. He kept key armored reserves and strong formations waiting for a “real” invasion at Calais.
This delay mattered enormously. German doctrine required rapid counterattacks to throw an amphibious landing back into the sea. Instead, the Allies secured beachheads, built up men and matériel, and achieved the breakout that liberated France.
Hitler’s rigid command style worsened the problem. Field commanders lacked authority to redeploy major units quickly without his approval, and on D-Day, Hitler was asleep during the critical early hours. His staff delayed waking him, further delaying the release of armored reserves.
By the time Germany recognized Normandy as the main invasion, the opportunity to crush it was gone.
The “deception” wasn’t the mistake by itself—being fooled happens in war. The mistake was Hitler’s stubborn attachment to a single expectation even as evidence changed on the ground.
Sources: The National Interest, Wikipedia, Encyclopaedia Britannica, Imperial War Museums, National WW2 Museum
