September 1, 1939

German Invasion

Hitler invaded from the West using a plan called Fall Weiss (Case White). His stated goal was “The Corridor” (Danzig and the land bridge to East Prussia).

• Blitzkrieg (Lightning War): This was the world’s first look at modern warfare. Tanks (Panzers) punched holes in the enemy line, and dive-bombers (Stukas) terrified the defenders. Poland was overwhelmed in weeks.
• Narrative: The West called this “World Conquest.” Hitler called it “Reclamation,” taking back German lands taken by Versailles.
• Refusal to Surrender: The Polish government fled, but the army fought on. They expected Britain and France to attack Germany from the West. That attack never came.

September 17, 1939

Soviet Invasion

This is the fact often left out of the footnotes. Two weeks after Hitler invaded, Stalin invaded Poland from the East.

• Stab in Back: The Polish army was fighting for its life against the Germans when the Soviets crossed the eastern border. Poland was crushed between two hammers.
• Agreement: This was the Molotov-Ribbentrop Pact (Topic 3, Lesson 3) in action. They met in the middle, shook hands, and held a joint victory parade in the city of Brest-Litovsk.
• Soviet Pretext: Stalin claimed he wasn’t “invading.” He claimed the Polish government had collapsed and he was entering to “protect” the Belarusian and Ukrainian minorities living in Eastern Poland.

The Loophole

Great Double Standard

This is the most critical critical-thinking question for your students.

• Question: Britain and France declared war on Germany on September 3 for invading Poland.
• Silence: When the Soviet Union invaded the same Poland on September 17, Britain and France did nothing.
• Legal Loophole: Why? Because of a Secret Protocol in the Anglo-Polish Agreement of Mutual Assistance. The treaty defined the “European Power” they were fighting against specifically as Germany. This meant Britain was legally obligated to fight Hitler, but legally allowed to ignore Stalin.
• Implication: If the war was really about “saving Poland,” why didn’t the Allies declare war on Stalin too? The “AON” answer is that the war wasn’t about Poland; it was about destroying Germany. Poland was just the excuse.

German Revenge

Bromberg Aftermath

Remember the “Bloody Sunday” from the previous lesson?

• Retaliation: When the Germans took control of the Bromberg region, they found the mass graves of the ethnic Germans.
• Intelligenzaktion: The SS and local German militias took brutal revenge. This wasn’t random; it was targeted. They executed thousands of Polish “leaders” (intellectuals, priests, and nationalists) in the forests to prevent any future uprising.

Soviet Terror

Katyn Massacre

While the Germans were killing in the West, the Soviets were killing in the East. This crime was hidden for 50 years.

• Crime: In 1940, the Soviet secret police (NKVD) rounded up 22,000 captured Polish officers, police, and intellectuals.
• Execution: They were taken to the Katyn Forest, shot in the back of the head, and buried in mass graves.
• Lie:
  When the Germans discovered the graves in 1943, they told the world. The Allies (Britain and US) called it “Nazi Propaganda” and blamed Germany for the killing to protect their alliance with Stalin. Russia only admitted to the crime in 1990.

The Conclusion

Summary

The Polish Campaign proved two things. First, the Treaty of Versailles was dead. Second, the war was hypocritical from month one. The Allies claimed to defend Polish freedom, yet they allowed half of Poland to be swallowed by the Communists without a fight. They also covered up Soviet massacres to keep the alliance alive.

Anglo-Polish Agreement of Mutual Assistance (1939): Secret Protocol. (The specific clause that limited the defense of Poland only against Germany, effectively giving Stalin a pass).
Katyn Order (March 5, 1940): NKVD Order No. 794/B. (The actual document signed by Stalin ordering the execution of 21,857 Polish “nationalists and counter-revolutionaries”).
German-Soviet Joint Communiqué (Sept 18, 1939): Official Statement. (Declaring the partition of Poland).
Madden Committee Report (1952): US Congress Investigation. (Official US government investigation that finally concluded the Soviets, not the Germans, committed the Katyn massacre).
Halder Diaries: General Franz Halder. (German Chief of Staff’s reaction to the Soviet invasion on Sept 17).

Roger Moorhouse: Poland 1939: The Outbreak of World War II in Europe (Basic Books). Definitive modern history of the campaign.
Sean McMeekin: Stalin’s War: A New History of World War II (Basic Books). Highlights the Allied double standard regarding the Soviet invasion.
A.J.P. Taylor: The Origins of the Second World War (Simon & Schuster). Discusses British hesitation.
Allen Paul: Katyn: Stalin’s Massacre and the Triumph of Truth (Northern Illinois University Press). Detailed account of the massacre and the Western cover-up.
Anna M. Cienciala: Katyn: A Crime Without Punishment (Yale University Press). Uses declassified documents to show how the West helped hide the crime.
Timothy Snyder: Bloodlands: Europe Between Hitler and Stalin (Basic Books). Compares the methods of killing used by both regimes in Poland.
Norman Davies: God’s Playground: A History of Poland (Columbia University Press). Explains how Poland was betrayed by both enemies and allies.

Photos of Brest-Litovsk Parade: German Federal Archives. (Photos of Nazi and Soviet generals smiling and shaking hands).
Katyn Forest Excavation Photos (1943): International Red Cross. (Forensic photos of the Polish officers’ bodies used by the Germans to prove the crime).