The major development after the Polish campaign involved using armored forces to conduct the initial breakthrough even against prepared defenses. On February 7, at a war game held in Koblenz, Guderian proposed concentrating the armored forces for a drive across the Meuse River around Sedan, then expanding the bridgehead northwest toward Amiens. The Chief of Staff insisted on a measured buildup, waiting for the infantry before seeking to exploit the initial success. A month later, a second war game evaluated the same issue. This time the pressure from on high for using infantry to force the crossing was even stronger. Guderian and XIV Panzer Corps commander Gustav von Wietersheim responded that the proposed conservative employment of the armor was so likely to produce a crisis that they could have no confidence in a high command that ordered it.
These kinds of war games were intended to generate spirited debate with no hard feelings. But when two experienced senior generals flatly declared “no confidence” in a plan, it was the closest thing possible to saying “get yourself another boy.” This partly manifested the panzer troops’ new confidence. Arguably it also reflected a persisting sense at senior command levels that, for all their retraining, the foot-powered infantry of 1940 might not be the soldiers their fathers were in 1914. This was the time of the new men of the German army: the panzer troops.
The army faced a related problem: growing shortage of motor vehicles. As early as 1938, maintenance personnel had to cope with a hundred different models of trucks. That number had been reduced, but on the outbreak of war, confusion was restored by the commandeering of thousands of trucks directly from the civilian economy. Polish roads—or the absence of them—had been hard enough on the panzers. Supply columns had suffered losses in some cases more than 50 percent, many of them permanent. By 1940, write-offs had reached a point where the General Staff was considering replacing some trucks in infantry divisions with horse-drawn vehicles. Small wonder in such contexts that the concept of putting the mobile forces up front increasingly permeated thoughts about the coming campaign.
III
THE GENESIS OF the German strategic plan against the Western allies is familiar. Hitler wanted the Western campaign to begin immediately after the fall of Poland. The initial date of November 12 was a compromise with a High Command reluctant to mount an offensive under any circumstances. Its foot-dragging produced no fewer than 29 postponements and a concept for Case Yellow, the Western offensive, that involved sending 75 divisions, including most of the army’s mobile formations, into the Low Countries to engage the main Anglo-French strength in what was expected to be an encounter battle in central Belgium. Even before Hitler became directly involved in the planning process, this unpromisingly conventional proposal was generating increasing criticism. It incorporated no proposals for destroying enemy armed forces, speaking rather of creating favorable conditions for future operations. The High Command’s thinking seemed to go no further than punching a hole and seeing what developed. In that sense their proposal owed more to Ludendorff ’s abortive 1918 offensive than the Schlieffen Plan to which it has often been compared.
Interwar theorists of independent armored warfare like Fuller and Liddell- Hart tended to stress disruption—paralysis—as an end in itself. Cut an enemy’s nervous system and all that remained was rounding up the demoralized and hungry masses. By contrast, the High Command’s plan anticipated the kind of hard fighting that made decisions dependent on contingencies—including a solid probability of defeat at the hands of Allied armor. It required little more than back-of-the-envelope calculation to determine that the force-to-space ratios created by the proposed operation would invite exactly the kind of head-on engagements the army’s mechanized elite was ill- configured to fight. The consequences of defeat, or even stalemate, somewhere in Belgium were hardly likely to have involved strengthening either Hitler’s domestic position or Germany’s chances for victory.
German doctrine, both generally in the army and specifically in the armored force, was based on destroying enemy forces by breaking their will and their ability to resist. That was the principle of Vernichtungsschlacht, too often tendentiously translated as “battle of annihilation” and then interpreted literally. That was also the basis of the alternative concept put forward by Erich von Manstein, then-chief of staff to Army Group A. Manstein’s proposal was intended as much to provide a central role for his commanding general, Gerd von Rundstedt, as to furnish a program for victory. His projected thrust through the Ardennes would transform Rundstedt’s army group from a secondary player to the campaign’s focal point. Broken terrain made the option a risk—but a calculated risk, taking maximum advantage of the principal German force multipliers: leadership and technology. Hitler, disgruntled by his generals’ conventionality and angered by a security breach that put copies of the original plan in Allied hands, took advantage of Manstein’s temporary presence in Berlin to discuss his ideas. A few days later he issued a new operational plan: a Sichelschnitt (“sickle cut”) through northern France that would eventually put seven of Germany’s ten panzer divisions under Army Group A.
The intelligence service’s conviction, repeatedly tested in war gaming, was that the French and British high commands would respond slowly to that kind of surprise. Since 1933, generals and politicians on both sides of the English Channel had failed to understand German intentions and German decision-making processes. Instead they had grown accustomed to putting unexpected events into preconceived models, from a postulate that Hitler ultimately would not risk war to a belief that Germany would attack in Belgium because it suited the Allies’ book that it do so. Both common sense and thinking outside the box were sacrificed to habit—and in the case of the French, to logic. Allied intelligence provided more than enough evidence to turn eyes to the Ardennes in the spring of 1940. Instead, the Allies believed what they needed to believe about the German operational plan, and kept on believing it during those few crucial days when the German spearheads sliced across their rear toward the Channel.
Had Allied leaders anticipated a major offensive through the Ardennes even as a contingency, it is almost inconceivable that the catastrophe of 1940 would have taken place as it did. Indeed, the alternative of a French victory parade down Unter den Linden was a real possibility. France in 1940 was arguably in less danger of moral collapse than a Germany whose public morale was in good part a consequence of what seemed Hitler’s unbroken string of rabbit-out-of-the-hat successes. German soldiers as well as French ones panicked on the battlefields of 1940. Many of the shortcomings in training and equipment France faced in the 1930s had been addressed and overcome or moderated by the spring of 1940. The British Expeditionary Force (BEF) had done a good deal to improve its effectiveness since its initial deployment across the Channel. The Allies had “equipment for victory”: powerful air forces, a fully motorized BEF, and around 3,500 tanks, many of them superior to the lighter models still predominant among the 2,300 German ones. And the French expected to win when the fighting started. The French army may have been less effective than its enemy on the tactical level, and its commanders on the whole may have been a cut below their German counterparts. However, nowhere in French circles or among France’s allies was there serious doubt of the French ability at least to stop any German offensive in its tracks. That kind of confidence is itself a force multiplier not to be despised.
The Germans thus benefited disproportionately from an obliging enemy. An obliging enemy is not an enemy that makes mistakes, but rather one that behaves as though the opposition prepared his orders. “Obliging,” however, is not a synonym for “stupid.” Chief of Staff Franz Halder was won over by Sichelschnitt at least as a calculated risk preferable to the existing alternatives, but realized its success depended on keeping the Allies’ attention focused on the Low Countries. German military planners’ focus on tactical and operational levels at the expense of strategy and policy has been so often repeated it has become a shibboleth. Halder and his subordinates were well aware that the Netherlands were reluctant to cooperate militarily with anyone—even neighboring Belgium. Belgium had begun developing a defensive line facing Germany at the start of the war. It also briefly deployed its army on both the French and German frontiers, and the government had repeatedly emphasized the worthlessness of any Allied assistance that arrived after Belgium had been invaded and devastated, as had been the case in 1914. Immediate and convincing Allied commitment in the face of a German initiative was correspondingly imperative. The dynamics of any battle fought in Belgium would change significantly should Belgian involvement be less than enthusiastic, to say nothing of the probable consequences of the non-participation of Belgium’s two dozen divisions.
How, then, to keep the Allies convinced that what they wanted to do was also operationally necessary? The developed German plan used almost a third of the armored force as bait. The 9th Panzer Division, with the fewest number of tanks, would cooperate with the Luftwaffe’s paratroopers and the army’s air-landing division to strike the Netherlands in a “shock and awe” operation. Two panzer and a motorized division under Army Group B would provide the mobile core of an otherwise foot-powered thrust into Belgium. A chess player might speak of a knight’s move, a bullfight aficionado might think of a matador’s cape. But the other half of the knight fork, the sword delivering the killing blow, was Panzergruppe Kleist. Five armored and three motorized divisions, plus the Grossdeutschland Regiment, would pass through the Ardennes and force their way across the Meuse River into northern France. An entire antiaircraft corps was folded into the Panzergruppe to compensate for fighter planes with other assignments. Its right flank would be covered by another two-division panzer corps under Hermann Hoth.
The operation was still high-risk. It involved more than 130,000 men and more than 1,500 armored vehicles—many of both nose-to-tail from the border all the way back to Koblenz. No tank-and-truck force approaching that size had ever been deployed before. Could it fight through a forest, breach prepared defenses, and cross a major river without sacrificing its fighting power?
As much to the point, could Panzergruppe Kleist keep out of its own way once the fighting started? Ewald von Kleist was a cavalryman whose first experience with armored troops had been as a corps commander in Poland. He had done well enough handling two panzer divisions, but his current assignment reflected less his operational skill than his emotional steadiness and mental toughness. He had a reputation for bringing subordinates to his point of view without pulling rank. If the Panzergruppe was the Schwerpunkt of Case Yellow, the Schwerpunkt of the Panzer Group was Guderian’s XIX Corps. “Der s
chnelle Heinz
” (“Hurrying Heinz”), as the men called Guderian, far overshadowed the other two corps commanders in terms of talent and charisma. They would take their leads from Guderian. He could make the sickle cut work—but like a fine-tuned engine, he needed a governor to prevent overheating. That was Kleist’s job, much as in World War I Hindenburg had acted as the nitrogen to Ludendorff ’s oxygen in the duo’s best days.
Army Group A’s headquarters rejoiced in its new role but was less pleased with the instrument for achieving it. Nothing like Panzergruppe Kleist had ever existed in the German command structure. Armies and corps, yes, but a “group” was generally understood as a temporary organization for secondary missions. Rundstedt left no doubt that the Panzergruppe as a concept was on trial by keeping it organically subordinate to one of his field armies during the campaign. This was anything but a vote of confidence, and proved a constant source of confusion, friction, and bad temper. It also served to galvanize Kleist’s professionalism and his professional ambition.
Since the First World War, French military authorities had routinely described the Ardennes as impenetrable to armored vehicles—“Europe’s best tank obstacle,” in the words of French commander in chief Maurice Gustave Gamelin. The impenetrability was not taken literally, but the French were convinced that even a full-scale offensive would take no fewer than five days—more likely nine—to push through the Ardennes, and about two weeks to attempt a crossing of the Meuse. Prewar intelligence reports of German intentions to attack through the Ardennes were processed as referring to no more than a secondary offensive. Initial reports of massive tank columns seemingly everywhere in the forest were dismissed as first-battle jitters. Besides, even if the Germans made it through the trees, they would surely be stopped by the river.
In Belgium, Army Group B did its job to near-perfection. A day’s initial delay due to blown bridges only encouraged the Allies to rush into Belgium and assume defensive positions along the Dyle River, reinforcing and supporting the Belgians. It was according to plan—the Dyle Plan. French generals and staff officers were students and creatures of a doctrine emphasizing the importance of a firepower and management. They had no intention of playing to the German army’s obvious strength by seeking an encounter battle of the classic sort, as opposed to using armor in defensive contexts along a line offering a shorter and stronger position than the one defined by the Franco-Belgian frontier.
Arguably the Germans’ greatest success at the strategic level, however, was achieved in Holland. Gamelin was committed to—one might say obsessed with—fighting as far away from French soil as possible. In pursuit of that design, he had reconfigured the employment of the mobile strategic reserve created with considerable effort during the 1930s. Originally it was projected that reserve would be deploying around Reims for use against a German invasion anywhere from Switzerland to the Low Countries. The final “Breda Variant” of the Dyle Plan, adopted in November 1939, projected using it, organized as the 7th Army, to drive into Holland and extend the left flank of an Allied position Gamelin expected would stop the Germans in their tracks—or close enough to that for military purposes. And then one would have most of Belgium to establish a killing ground for the managed battle that would decide the war.