As we approach June 6th, discussions inevitably turn to D-Day.
Why were the Allies successful? Why did the Germans fail?
Whenever these conversations come up among friends, fellow history buffs, and gaming buddies, I often find myself shaking my head because I think many people miss the most important point.
The Germans were not surprised that the Allies could win D-Day.
They expected it.
In fact, many German planners understood that if the Allies landed in force, they would probably win D-Day, D+1, and perhaps even D+2.
What they did not believe was possible was winning D+3.
Or D+14.
The German assumption was simple: once the Allies were ashore, German reserves would counterattack, contain the beachhead, and eventually push the invasion force back into the sea.
Why were they so confident?
Because they understood a fundamental reality of amphibious warfare.
You cannot sustain a modern army without logistics.
An army needs food, ammunition, fuel, medical supplies, replacement equipment, and reinforcements. Military planners often summarize these requirements as Beans, Bullets, and Black Oil.
The Germans knew they could not defend every mile of the Atlantic Wall. They lacked the manpower, equipment, and mobility necessary to stop every possible landing.
Instead, they focused on what they believed was essential for a successful Allied campaign:
A deep-water port.
Without a major port, the Germans believed the Allies would be unable to bring enough supplies ashore to sustain an offensive.
This wasn't an unreasonable conclusion.
German intelligence officers carefully studied Allied amphibious operations in North Africa, Sicily, Italy, and the Pacific. They looked at how American and British forces landed and how they sustained those operations.
They even identified what they believed was a flaw in American amphibious doctrine.
Most Allied landings had occurred near high tide. As the tide receded, landing craft often became trapped on obstacles, sandbars, and beaches. The Germans concluded that future invasions would require enormous numbers of landing craft, support vessels, and manpower simply to maintain the flow of supplies.
What never occurred to them was that the Allies would solve the problem in entirely new ways.
First, the Allies planned to land on a rising tide, accepting greater risk from beach obstacles in exchange for maintaining mobility.
Second—and far more importantly—they planned to bring the port with them.
The Mulberry Harbors remain one of the most remarkable engineering achievements of the war. Entire artificial harbors were assembled and towed across the English Channel, allowing supplies to be unloaded directly onto the beaches.
To German planners, the concept was almost unthinkable.
Ports were fixed structures. They existed in cities. Armies captured them.
The idea that an invading force could create a deep-water port where none existed simply did not fit within their understanding of how war worked.
Ironically, the Germans were not entirely wrong about the logistics problem.
On June 19th, less than two weeks after the landings, a severe storm swept through the invasion area. One of the Mulberry Harbors was heavily damaged and the American harbor off Omaha Beach was effectively destroyed. Had the Germans been correct about the Allies' inability to sustain themselves without a major port, the invasion might have stalled right there.
Instead, Allied logisticians demonstrated another innovation the Germans had underestimated.
Supplies continued to flow across the beaches.
By utilizing amphibious trucks, specialized landing craft, temporary piers, and an astonishing amount of organization, the Allies unloaded men and materiel at rates the Germans had believed impossible. The beaches themselves became the port.
In many ways, this was the real Allied victory at Normandy.
Not the landings on June 6th.
Not even the successful establishment of the beachhead.
The victory came from proving that a modern army could be supplied over open beaches long enough to build up overwhelming combat power.
The Germans had planned to defeat an enemy that required a port.
The Allies arrived having already solved that problem.
This is one of the reasons I believe the Germans misjudged Normandy.
It wasn't because they were stupid.
It wasn't because they lacked competent officers.
It wasn't even because they misunderstood Allied capabilities.
They made a reasonable assumption based on every historical example available to them.
What they failed to anticipate was that the Allies would fundamentally change the rules.
And when your entire defensive strategy depends upon assumptions about what your enemy cannot do, discovering that they can do it anyway is often the beginning of defeat.
