by Paul Kennedy
General Fredendall’s units were simply the fifth—or was it the seventh or tenth?—national army to experience the most uncomfortable military situation of the Second World War: being attacked by Wehrmacht forces who struck hard at first, and if necessary struck hard again in a later counterattack, to shock the enemy, dislocate his communications, weaken his morale, and paralyze his high command. On most occasions, the first, blindingly fast assault was enough. If resistance on the ground began to grow, the German units pulled back—but only to prepare to strike again. This, at least, had been the story from 1939 until the end of 1942.
Even knowing of the Third Reich’s final and total defeat, a historian writing about these events seventy years later can only wonder at what Williamson Murray termed in his book “German military effectiveness.”3 The Wehrmacht blew apart a large, gallant, but highly disorganized Polish army within two weeks, in September 1939. There are reasons to discount the significance of this extremely lopsided fight, except that all of the components of this new way of warfare were deployed: the Luftwaffe immediately took control of the air, destroyed Polish air bases and scattered army columns, then proceeded to devastate Warsaw; the fourteen mechanized divisions swept past the badly emplaced Polish infantry, brushed aside the cavalry, and raced toward all the major targets—Lodz, Cracow, Lwow. While masses of Polish soldiers were being steadily herded into encircled positions, one of the armored divisions of Walther von Reichenau’s Tenth Army raced to the outskirts of Warsaw in a week. Soon it was all over.
After spending some time during the so-called Phony War assessing how they could do even better during their next battles, the German panzers, infantry, and air forces struck westward and northwestward in the spring of 1940. The smaller armies of Denmark, Belgium, and the Netherlands were engulfed, perhaps understandably, but the swift Nazi takeover of Norway—in the Royal Navy’s front yard—was astounding. Even more astounding, in one of the epic battles in the long military history of western Europe the massive French army was crushed and a half-trained British Expeditionary Force bundled out of the continent only a month or so later. Evidently the Wehrmacht’s swift defeat of Poland was no fluke. After all, the French had larger ground forces than Germany (sixty-five active divisions for the French, compared to fifty-two active divisions for the Germans) and more tanks, including some heavier ones.c The French had been preparing for two decades to counter a German attack in the West, and they would be joined by the British Expeditionary Force and a Belgian army reluctantly sucked into this war. But the French air force was weak and outdated, and so the Luftwaffe dominated the air. The unorthodox German panzer thrust through the Ardennes dislocated the French high command, which simply could not keep up with the pace and boldness of Heinz Guderian’s advances toward the Channel—even his Wehrmacht superiors and Hitler himself were unnerved as they watched this unexpectedly fast victory, fearing the panzers might go too far and get trapped.
By June 1940 France was done for, and Britain stood alone. The whole geopolitical and military shape of the war was transformed. Stalin was amazed and anxious, knowing that his purge-weakened armies were nowhere near ready to fight. The American government was transfixed. Mussolini rushed to join Hitler. The Japanese recalculated their options. The European war was not even ten months old, and the world had been turned upside down. Little wonder the term “lightning war” seemed so appropriate.
For Britain and its partners, 1941 was no better. Yugoslavia’s political tilt against the Axis that spring had been punished by an enormous, swift invasion that carried on through the southern Balkans to overwhelm Greece and then capture Crete in a bold parachute attack. Was there a particular British regiment that was pushed out of Norway, then pushed out of France, only to be pushed out of Crete in May 1940, a fate magnificently imagined by Evelyn Waugh in his great wartime trilogy?4 If so, that regiment might well have been pulled back to Egypt, where soon it would have encountered the fast-moving and highly dislocating assaults of Rommel’s Afrika Korps. By that time, of course, the much larger Operation Barbarossa had begun, and German panzers were slicing through the Ukraine, leaving millions of Russian soldiers to be rounded up and herded to their fate. Really, the American soldiers crushed in the Battle of the Kasserine Pass had little to apologize for; it was simply their turn to get beaten up.
What follows in the rest of this chapter are two related questions. The first is why the Germans were so good operationally and tactically, and if they were that good, how on earth did one defeat them? The second is more general: did offensive warfare stand a better chance of claiming victory than any defensive strategy whatever? Assuming bold leadership and well-trained troops in the attacking army, would this phenomenon of lightning war almost always succeed—or was it critically affected by other factors such as time, space, and sheer numbers? It makes sense to treat the second, more general question first before looking at the reasons for the Wehrmacht’s performance in the Second World War; by doing so we can arrive at a better understanding of why the land battles in western Europe, Russia, and the Mediterranean unfolded the way they did. The history of warfare is littered with examples of swift and spectacularly successful campaigns—probably nothing in modern times equals the achievements of Alexander the Great and Genghis Khan in the rapid overthrow of enemies and the extensive conquest of lands. No doubt the wide-open spaces across which they chiefly fought explain a great deal; with a decisive leader and mobile shock forces, an army could travel a long way in a week. This may also explain, conversely, why Europe’s topography of mountain chains, dense forests, extensive swamps, and numerous rivers made complete control by any one power so very difficult.5 Aware of these constraints, the Romans kept to their limits, while the later Holy Roman Empires of Charlemagne and the Hapsburgs were those of a large regional power. The wars of the Middle Ages were chiefly slug-it-out affairs, and the arrival of newer defensive fortification designs after 1500 put the emphasis upon laborious siege warfare.
Even in Europe, there were historic exceptions: dramatic and swift campaigns that threw the enemy off balance, because the attacking army was so well trained and motivated that geographic obstacles seemed to shrivel. The Duke of Marlborough’s dramatic march up the Rhine from the Netherlands to upper Bavaria (the Battle of Blenheim, 1704) is a good example. A half century later, Frederick the Great often stunned his enemies by the speed at which he switched his armies from one front to another, and sometimes divided his forces so that while one half contested the field of battle, the other was making a flank attack obscured by hilly terrain. Napoleon’s capacity for moving armies—very large armies, and at high speed—is legendary, and in 1866 and 1870 Helmuth von Moltke the Elder hit the Austrians and French so fast and decisively that those wars ended very swiftly.6
Yet these successes by lightning strikes were exceptional. Most of Marlborough’s other battles (Ramillies, Malplaquet) were great, static bloodbaths in the Low Countries. Surrounded by enemies on all sides in the critical period of the Seven Years’ War, Frederick had on many occasions no choice but to stand and fight. Try as they might, Napoleon’s great marshals and battle-hardened armies could never achieve a decisive victory in Spain: the terrain was too broken and harsh, giving the advantage to the many Spanish guerrilla groups that sprang up to conduct irregular warfare, and giving the advantage also to the British-led coalition under Wellington, that cautious master of situational battles. The most spectacular exposure of the weaknesses of the Napoleonic way of warfare came, of course, in France’s catastrophic defeat in the War of 1812, where the weather, sheer distance, and the Russian willingness to pull back hundreds and hundreds of miles made nonsense of the very idea of an early, decisive victory. Moltke concluded a decade or so after his 1871 victory over France that fast campaigning across industrialized western Europe by his Prussian armies would be impossible in the future: there were too many new urban zones, too many canals, too many railway embankments.
But the old field marshal was almos
t alone in this conclusion. His successors, Alfred von Schlieffen and Moltke the Younger, were mesmerized by the coming of railways and the telegraph, as were the generals in neighboring countries as 1914 approached. The advent of newer military technologies, such as modern aircraft and the tank in the years before the Second World War, saw another resurgence in the belief in swift military victories.
If we are looking to find the conditions, logically and logistically, in which lightning warfare doesn’t work, the first answer has to do with topography. A decisive victory isn’t achievable if the fighting has to take place across large mountain ranges, as the Wehrmacht discovered in trying to crush the partisans of Yugoslavia and Greece after 1941, and as, over centuries, successive waves of invaders have discovered in the high peaks of Afghanistan. Dense jungles, such as those in the southwestern provinces of China and across all of Southeast Asia, confirm this obvious military point: difficult physical circumstances tend to equalize the contest, even if one side possesses much more fighting power than its opponent (as was evidenced in Vietnam). And wide deserts, with hundreds of miles of shifting sands, definitely restrict the bolder Rommels of the world and give advantage to the more cautious Montgomerys. Great rivers, miles across from one bank to the other, slow down offensives; even if the attacking army has pontoons and other bridging equipment, such heavy stuff may have to be brought considerable distances to reach the water’s edge. Topography does not remove human agency, but the strategic planner who sees how best to exploit it will aid his commanding generals greatly.
Two further reasons, also very obvious, complete the picture. Fast mobile warfare leading to a swift and decisive victory in the field will, logically, not occur when the defensive armies themselves are too strong, too entrenched, too numerous to permit it. This would be true whatever the geographic extent of the battle zone. Yet it is also true that fast, aggressive forms of operation will most likely falter, then fail, if the attackers have to fan out over an increasingly broad area of land, with the leading troop units ever farther from the home base, each other, and their supply lines.
So much for the historical and abstract theory of blitzkrieg, of swift, aggressive, and shocking warfare conducted by forces that usually were also very good at smart counterattack. But what exactly did it mean in the case of the Wehrmacht’s operational performance during the Second World War? In the context of modern, industrialized warfare, the internal combustion engine, armored and armed vehicles, railways, and aircraft were melded into a form of fighting that appeared to contemporaries to be totally new and could transcend the larger geographic constraints of earlier eras. If proof were needed, one need look no further than the German tanks bursting through the forests of the Ardennes in May 1940.
And why was everyone so astonished at these very short campaigns? It was because almost everyone’s image of great-power land warfare had been shaped by the experiences of the grinding, static, slogging-it-out battles of the First World War, particularly in the campaigns along the Western Front and in northern Italy. At the Somme, at Verdun, at Passchendaele, and along the Isonzo, hundreds of thousands of soldiers were killed for a few miles gained. Sometimes the attackers, after months of fruitless assaults, ended up right back where they had started. This was the reality of modern industrialized war, as confirmed and chronicled in the histories, memoirs, and literary writings of the 1920s and 1930s.
What almost all of this literature missed was that in the closing years of the war certain military staffs had privately figured out how to break the deadlock of static trench warfare. The first changes came, unsurprisingly, in eastern Europe, where the lengths of the fronts were far greater and thus less densely held than along the Western Front. The Brusilov Offensive of summer 1916, when the Russian army overran the flaccid Austro-Hungarian forces, had succeeded because the attackers did not use massive Haig-like bombardments (they had too little ammunition) against the sluggish defenders; instead, they employed surprise, and in various places attacked shortly after they commenced firing. A German offensive around Riga in the next year used the same principles of shock, swiftness, and going around obstacles. In 1917 also, Italy suffered its biggest defeat at Caporetto, when fast-moving German units (including a young Erwin Rommel), sent to reinforce the Austro-Hungarian armies, made a spectacular breakthrough and compelled the Italian high command to call for Allied assistance. Perhaps the most important point about all this, as Timothy Lupfer argued, was that the Prussian General Staff allowed midlevel officers to circulate impressions, ideas, and experiences from their respective fronts, to stimulate initiative.7 If surprise assaults by well-trained infantry had worked in the Baltic, why not see if they might also work in Italy, or even in the West?
Slowly, roughly, the German army stumbled toward newer tactics and, of equal importance, newer types of troops: shock troops, better-trained, equipped with a new package of weapons (machine guns, grenades, wire cutters), and encouraged to press forward swiftly and move around enemy strongpoints. Meanwhile, on the Western Front, the British Army was at last coming up with its own way of cracking the trench warfare deadlock, a mechanical way, in the form of the first tanks; despite many early setbacks, they intervened to great effect in the August 1918 offensives. In the age-old tale of the ebb and flow contest of offensive and defensive warfare, the offensive had once again taken over.8 Here, in mobile strikes and fast-moving incursions, was the future of war, and the intellectual high priests of this latest “military revolution,” such as Liddell Hart and General J. F. C. Fuller, were to expend all their energies after 1919 in preaching the new gospel. Technology had conquered topography, newer types of armies could go any-where, and if the forward columns didn’t stop, the enemy’s nervous system would be paralyzed. Yet none of the armored-warfare enthusiasts considered that the greatest attempt at a decisive, swift victory—Ludendorff’s massive offensive in the West in spring 1918—had achieved significant advances initially but in the end could not get through the opposing defenses because the Allies’ firepower was too deep and the room for maneuver was far too small.
The lessons drawn from the First World War by the military experts about the potential of offensive mechanized warfare were therefore very mixed. The French high command, conservatively but rather logically, drew the 1918 lesson that only strength in depth had saved the Republic and that if it was attacked by Germany in the future, the best strategy would be a defensive one. This led it to create an even greater physical barrier against invasion in the form of the Maginot Line. In Great Britain, the armored-warfare enthusiasts, Fuller perhaps in particular, argued for all-tank forces, expanding outward from the breakthrough points and paralyzing the enemy’s nervous systems; Liddell Hart pushed for the indirect approach to battlefield victory, which also involved swift-moving attacks but by mixed military units making flank approaches or landings from the sea. Large-scale tank maneuvers on Salisbury Plain in the late 1920s showed that this new type of warfare had a future. So, despite the opposition of the cavalry regiments, the British Army pioneered mechanization until the crimping economies of the 1930s. The Americans, having reluctantly come over to Europe to squash the enemy in 1918 by massive material superiority (as had happened in the Civil War between the North and the South), were not interested in planning for another great war in Europe; they went home and demobilized. The early Red Army under Trotsky, then more professionally under Tukhachevsky, studied this debate and discussed what were called “deep battle” tactics, until Stalin’s manic purges in the late 1930s brought everything to a halt. And Japan’s planned zones of expansion—chiefly rivers, deltas, and jungles in Asia—were not suitable for tanks, except for very light ones that could manage the narrow roads and wooden bridges.
This left the German military, massively reduced in troop numbers and weapons systems by the Treaty of Versailles, battered by the failing Weimar economy, and marginalized by the corrosive party politics of the time, to wonder how it might recover its old fighting power. With the comin
g of the Third Reich in 1933, the generals began to see a steady and then dramatic inflow of resources for a military buildup. Most of the senior officers were Prussian conservatives of a traditional bent; their feeling was that the more infantry and artillery divisions, the better. But there was also a sufficient sprinkling of more radically minded officers—Guderian, Manstein, Hasso von Manteuffel, Rommel—to urge the case for fast mobile warfare. The Wehrmacht that opened the Second World War with the vicious assault upon Poland reflected this uneasy balance between old and new, with a small number of mobile motorized and panzer units and a preponderance of slower-moving, often horse-drawn divisions. Still, the faster forces, aided now by their own tactical air forces, had a punch that no one else possessed and the potential to execute that desirable, almost mythical battlefield operation, the Kesselschlacht.d They also had a Fuehrer who wanted fast results.