The Road to War: Germany’s Strategic Dilemma After Poland

By the summer of 1940, Germany stood at a crossroads following its swift conquest of Poland. The rapid victory had come at a cost – now the Third Reich faced the specter of a two-front war that had haunted German strategists since the days of Bismarck. Adolf Hitler, ever the opportunist, recognized that time worked against Germany. The Führer’s strategic vision focused on what he called “securing living space” by crushing Western powers before they could fully mobilize their superior industrial resources.

The situation presented a paradox. While Germany’s military had performed brilliantly in Poland, its western frontier remained vulnerable. The German defensive line, known as the Westwall or Siegfried Line, paled in comparison to France’s formidable Maginot defenses. Meanwhile, Britain and France had declared war but remained curiously passive during the Polish campaign – a period later dubbed the “Phony War” or “Sitzkrieg.”

The Original “Case Yellow” and Its Flaws

In November 1939, German High Command (OKH) produced the initial invasion plan codenamed Fall Gelb (“Case Yellow”). This conservative scheme bore striking resemblance to the 1914 Schlieffen Plan, calling for a strong right-wing thrust through Belgium and northern France. The objective was limited – securing Channel ports rather than decisive victory.

Several senior commanders immediately recognized the plan’s shortcomings. General Erich von Manstein, chief of staff for Army Group A, became its most vocal critic. He argued that repeating the Schlieffen approach would produce another stalemate, as Allied forces would anticipate this obvious move. The plan’s unimaginative nature troubled Manstein, who later wrote: “I at least felt it to be a disgrace that we should be copying the famous Schlieffen plan.”

Manstein’s Revolutionary Alternative

Manstein developed an audacious alternative that would become one of history’s most brilliant operational plans. His proposal contained three key innovations:

1. Shifting the main effort to Army Group A in the center
2. Concentrating panzer divisions to punch through the Ardennes
3. Aiming for decisive encirclement rather than territorial gains

The Ardennes region, considered impassable for tanks by French strategists, became the linchpin of Manstein’s scheme. He consulted panzer expert Heinz Guderian, who confirmed that armored units could navigate the forested terrain. This breakthrough meant German forces could bypass the Maginot Line entirely and achieve complete strategic surprise.

Hitler’s Intervention and the Plan’s Adoption

Manstein faced fierce resistance from conservative generals like Halder and Brauchitsch. His persistence nearly cost him his career – in January 1940, he was “promoted” to command a corps, effectively sidelined from planning. However, fate intervened through two critical events:

First, the Mechelen Incident on January 10, when a German courier plane carrying parts of the original plan crashed in Belgium. This security breach forced Hitler to reconsider the compromised strategy.

Second, Manstein’s February 17 meeting with Hitler proved decisive. The Führer, who had been contemplating similar ideas, immediately grasped the plan’s potential. As Manstein recalled: “Hitler understood its possibilities with lightning speed.” By late February, the revised plan – now called Sichelschnitt (“Sickle Cut”) – became official strategy.

The Execution: Blitzkrieg Unleashed

When the offensive launched on May 10, 1940, German forces achieved complete surprise. Army Group B’s feint into Belgium succeeded brilliantly, drawing Allied forces northward. Meanwhile, the main armored thrust through the Ardennes – led by Guderian’s XIX Panzer Corps – achieved the impossible, crossing the Meuse at Sedan within three days.

The psychological impact proved devastating. French commanders, wedded to static defense doctrines, couldn’t respond to the fluid battlefield. By May 20, panzers reached the Channel, trapping Allied forces in Belgium. The Dunkirk evacuation saved the British Army but couldn’t prevent France’s collapse six weeks later.

The Legacy of a Military Masterpiece

The Manstein Plan’s success transformed modern warfare in several ways:

1. Doctrinal Revolution: It demonstrated the decisive potential of combined arms warfare and operational maneuver over positional tactics.

2. Psychological Impact: The shock of rapid collapse shattered French morale and permanently altered perceptions of German military superiority.

3. Strategic Consequences: France’s defeat left Britain isolated and enabled Hitler’s turn toward the Soviet Union.

4. Planning Methodology: The emphasis on surprise, concentration of force, and exploitation of enemy assumptions became standard military principles.

Historians continue debating whether the plan’s success resulted from German brilliance or Allied failures. The French High Command’s rigid thinking and poor intelligence assessment certainly contributed. As one French officer lamented: “We had the weapons but not the doctrine.”

The 1940 campaign remains a cautionary tale about the dangers of fighting the last war. While France prepared for another 1914-style conflict, Germany rewrote the rulebook. Manstein’s operational vision, combined with Guderian’s tactical expertise and Hitler’s willingness to gamble, created a perfect storm that changed military history forever.

Today, the campaign serves as a classic case study in military academies worldwide – a testament to how innovative thinking can overcome material disadvantages and reshape the strategic landscape in breathtaking fashion.