Germany’s opening gambit of World War One, the execution of the Schlieffen Plan, was both bold and aggressive. It propelled German troops into Belgium and France, resulted in massive casualties for both sets of belligerents, and effectively ensured British entry into the conflict. For all its daring, however, the Schlieffen Plan failed to achieve its objectives of decisively defeating the French Army and forcing France from the war. This paper examines and evaluates the Schlieffen Plan in three sections. The first section examines the motivating factors driving the German General Staff to devise the Schlieffen Plan by looking at the international and strategic environment in which Germany found itself. The second section describes the unfolding of the Schlieffen Plan, noting its operational effectiveness and highlighting its successes and failures. Finally, the paper concludes with a holistic analysis of the Schlieffen Plan at both the strategic and operational levels. While the specific conclusions of the paper are detailed at length in the final section, the fundamental argument is that the Schlieffen Plan failed at both an operational and strategic level. It relied on unfounded and overly optimistic assumptions about the tactical superiority of German troops, subordinated political objectives to military preferences, and imperiled Germany’s position by severely weakening the Eastern front and provoking British entry into the war.
The Origins of the Schlieffen Plan
The Schlieffen Plan had many progenitors, but its origins can be traced back to the period following the 1870-1871 Franco-Prussian War. That conflict decisively changed the balance of power in Europe by creating, for the first time in history, a united Germany. The nature of Germany’s birth ensured a degree of lingering animosity between Berlin and Paris, as Germany’s unification was inextricably tied to France’s defeat at the hands of Prussia. Perhaps more consequential, however, was Germany’s annexation of the French territory of Alsace-Lorraine. This territorial seizure created powerful irredentist pressures in France and served to further exacerbate Franco-German animosity. Thus, German policymakers and generals had good reason to worry about future hostilities with France. German leaders also had to plan for potential conflict with Russia, as it continued to grow as a military and economic threat to the German Empire’s eastern borders. These twin pressures led to the first iteration of the ideas that would ultimately coalesce into the Schlieffen Plan.
The first version of the Schlieffen Plan was devised by Chief of Staff Helmuth Karl Bernhard Graf von Moltke (Moltke the Elder) in 1888 and sought to replicate Germany’s 1871 victory by striking at Paris. However, in this version of the plan, the German General Staff planned to strike at Russia first, as they feared that their initial assumptions about the length of time that Russia would require to mobilize were unduly optimistic.[i] The decision to strike Russia first was ultimately reversed by Alfred von Schlieffen, who became Germany’s third Chief of Staff in 1891, and thus the Schlieffen Plan was born.[ii] Schlieffen assessed France to be the greater threat, as he realized that its armed forces were both better equipped and more easily mobilized than those of the Russian Empire. As a result, he planned to commit as many as 82 of Germany’s proposed 96 divisions to the Western front stretching between Metz and Aachen.[iii] The idea was to use these troops as a sledgehammer to strike through the Benelux in order to bypass French border defenses before turning southwest to encircle and annihilate French forces attempting to defend Paris.
This plan was driven by Germany’s unfortunate position vis-à-vis Russia and France. The two countries had formed a defensive alliance in 1894, which committed them both to “mobilize immediately the whole of their forces and deploy them with such speed that Germany shall be forced to fight simultaneously on the East and on the West.”[iv] By 1904, Great Britain also seemed increasingly like an adversary following its signing of the Entente Cordial with France. This threat was compounded in 1907 when Great Britain and Russia signed the Anglo-Russian convention.[v] While London was far from certain to intervene against Germany given its detached diplomatic posture, France and Russia, alone, were significant threats: Their combined GDP was 20% greater than the combined economic output of Germany and its ally Austria-Hungary, and Russia’s population was 33% greater than Germany’s, granting it an enormous manpower advantage. In a worst-case scenario involving British and Belgian support for France and Russia, Germany would face a force of 5,726,000 soldiers in 218 infantry and 49 cavalry divisions. Even when one aggregates German and Austro-Hungarian forces – 3,485,000 soldiers in 137 infantry and 22 cavalry divisions – and accounts for their interior lines advantage, which allowed them to more rapidly shuttle units between battlefields and fronts, the German General Staff faced a numerical shortfall of monumental proportions.[vi]
The final version of the Schlieffen Plan, developed by the nephew of Moltke the Elder, Helmuth Johannes Ludwig von Moltke (Moltke the Younger), responded to this disadvantageous situation by continuing to prioritize the defeat of France. Moltke the Younger, much like Schlieffen, aimed to quickly neutralize France. He then planned to use the highly efficient German railway system to shift the bulk of the German military east to engage the more slowly-mobilizing Russian menace. However, Moltke the Younger was more cautious than Schlieffen, and he therefore modified the plan in a manner that marginally reduced the number of divisions tasked with executing the right hook through the Benelux.[vii] Specifically, his qualified plan would deploy a greater number of troops south of Metz in order to repulse a French attack on Alsace-Lorraine and protect the Saarland, an industrial hub for Germany. This left only 54 divisions to execute the right hook. To compensate for this diminished right wing, Moltke the Younger reformulated the Schlieffen Plan to forgo an invasion of Holland. He also changed the operational objective of the right wing from advancing around Paris to simply pushing French forces to the southeast. The goal, of course, was to achieve a grand encirclement trapping the French between the reinforced German left wing and the inexorably advancing right wing.[viii]
The Schlieffen Plan was extremely risky, and it placed an enormous amount of faith in the German troops’ ability to achieve an almost unimaginable objective. However, when one realizes the dire strategic situation in which the General Staff found itself, the plan becomes more comprehensible. Simply put, it was a desperate gamble designed to overcome the challenge of a two-front war by exploiting Germany’s advantage in mobilization and access to interior lines to defeat Berlin’s quantitatively superior but more ponderous foes. The planning was conducted exclusively by the German General Staff, and it largely excluded civilian leadership and the Austro-Hungarian General Staff. As a result, the plan was highly technical and assiduously detailed, as one would expect of any product created by the extremely capable and detail-oriented German military. However, it relied upon several important but questionable assumptions and failed to consider important political realities and Austro-Hungarian limitations. As will be shown later, these failures eliminated many of the Schlieffen Plan’s supposed advantages.
The Schlieffen Plan in Action
The June 28, 1914 assassination of Austrian Archduke Franz Ferdinand in Sarajevo precipitated a crisis in Europe. After nearly a month of intense negotiating and brinksmanship, the inexorable slide toward war began. On July 23, the Austro-Hungarians issued a list of impossible demands to the Serbs, giving them only two days to respond.[ix] In response, Czar Nicholas II ordered Russian forces to prepare for partial mobilization.[x] The real turn toward crisis occurred on July 28, when Austria-Hungary officially declared war on Serbia and prompted Russia and France to begin mobilizing, which in turn led the German Empire to declare a state of emergency and begin calling up its own reserves.[xi] Germany occupied Luxembourg on August 2, and the full invasion of France through Belgium, as specified by the Schlieffen Plan, began on August 3.[xii]
Initially, Germany’s planned invasion seemed to be proceeding exactly according to expectations. The superb German railway network and reserve system allowed for the rapid mobilization and movement of troops to the front. Indeed, from the outbreak of hostilities to the capture of Liege on August 17, German trains transported 3 million soldiers and 850,000 horses to the front. The process succeeded like clockwork, which is demonstrated by Germany’s ability to organize 2,150 westward-bound trains – with one train crossing the Hohenzollern Bridge over the Rhine every ten minutes – without major incident.[xiii]
Germany’s initial target was Liege, which was an important railroad junction and would, therefore, help support German logistical requirements in Belgium and northern France. The pivot point for the turn into Belgium was just north of Lorraine, and the forces arrayed here included fifty-two divisions in three armies. The First Army, led by von Kluck, was composed of 320,000 men on the far-right wing. Further down the line were Büllow’s Second Army of 260,000 and von Hausen’s Third Army of 180,000.[xiv] These three armies surged into Belgium, pushing to Brussels before pivoting southwest toward Paris. Unfortunately for German leadership, Belgian troops did not meekly capitulate as they had assumed. Instead, they mounted a spirited defense of Liege.[xv] The city was surrounded and fortified by a ring of steel and concrete forts, and five days into the conflict the city still had not fallen. This city’s stubborn refusal to capitulate was, in part, assisted by the fact that the German attack occurred while mobilization was still ongoing, thus limiting the size of the force Germany could deploy. However, the inability to quickly take Liege created a huge bottleneck that threatened to halt the German advance in its tracks.[xvi] Meanwhile, both German and French forces were conducting limited offensives in the south around Lorraine. While the German Fifth and Sixth Armies were victorious, inflicting nearly 10,000 casualties on the French, they were themselves too broken to meaningfully pursue French forces.[xvii]
By this point, German forces had largely succeeded in pushing into Belgium, though progress was retarded by Belgian partisans and, more importantly, German fear of them. This contributed to a German overreaction, which alienated Belgian citizens and severely damaged Germany’s image abroad. Increasing Belgian resentment also forced a sizeable German force to remain behind to hold and pacify the region, slowing progress and reducing the number of units available for frontline service.[xviii] Despite these impediments to progress, good fortune shined on German leaders due to French incompetence as well as random chance. On August 21, French Commander in Chief Joseph Joffre misread German troop positions by failing to recognize that Germany had already fully deployed nearly all of its reserves to the front. As a result, he noted the strength of German forces in Belgium and Lorraine and concluded that their forces in the center must be weak. He thus ordered the French Third and Fourth Armies to attack the German pivot point in the Ardennes. Unfortunately for the French, the German position was formidable here as well, outnumbering the French 21 divisions to 20. The day the forces met was misty, and French reconnaissance completely missed the Germans. Thus, the French blindly crashed into German troops, whose superior numbers and howitzers, which granted an advantage over the French 75 mm field guns in the hilly terrain, led to catastrophic losses among French forces.[xix]
Two days after the French attack on the Ardennes began, French General Lanrezac ordered the Fifth Army to retreat, completely abandoning all French fortifications in the area and creating a rift with the British Expeditionary Force (BEF). The BEF made contact with von Kluck’s First Army on the 23rd, and while it executed a masterful delaying action, holding off 6 German divisions with only 2 divisions of its own and inflicting three times as many losses as it suffered, the arrival of German howitzers and infantry reinforcements compelled the British to fall back.[xx] At this point, the French were in tatters and their northeast was completely exposed to German attack. The French military had already sustained 260,000 casualties and were in full retreat. The one positive to emerge for the French from the complete collapse of the Ardennes offensive was that their units withdrew so quickly that German forces could not execute their planned encirclement. Thus, while shattered, much of the French Army remained intact.[xxi]
This point of the offensive was the best position Germany would ever enjoy, and it seemed as if their forces had achieved the impossible. However, it was at this moment that the inadequacies of the Schlieffen Plan began to emerge. The first problem was primarily one of logistical and technical limitations. The highly centralized nature of the plan combined with poor communication technology led to severe confusion in parts of the front. Moreover, Germany’s operational concept of Auftragstaktik, which gave commanders wide latitude to move as they saw fit, only magnified the divergence between the intentions of the General Staff and the actions of the commanders.[xxii] Supply became another issue. While the highly developed German train network allowed for rapid initial mobilization, the celerity it facilitated dissipated once formations advanced beyond rail terminals. German troops had to march hundreds of kilometers with heavy packs and uncomfortable clothes, and these problems were magnified by the fact that the First, Second, and Third German Armies had only 1,000 vehicles between them. These difficulties were further exacerbated by Belgian railway sabotage. The delays this created meant that German forces were unable to exploit the opening they had created by smashing French forces in the Ardennes.[xxiii]
These problems were compounded by two of Moltke’s decisions in the days after the Ardennes battles. First, he ordered further attacks in the south, with a particular focus on Nancy. This prevented the transfer of forces from the relatively quiet southern front to the higher-intensity right wing. Second, he ordered three army corps to reinforce forces in the east facing off against the Russians. This was largely a result of the Austro-Hungarian failure to deploy even a token force in Galicia to hold Russian attention, and it reveals the utter lack of coordination between the German and Austro-Hungarian staffs.[xxiv] The combination of these decisions led to an unnecessarily weak right wing that was vulnerable to French counterattack, and counterattack the French did.
Following the collapse of French and Belgian forces in the north, Joffre scrambled to cobble together a new army, designated the French Sixth Army. Concentrated around Paris, it was composed of reserve forces from within France’s interior and elements of retreating formations. While the French situation seemed quite dire, it is important to remember that the advantages derived from holding the interior lines – namely, the ability to quickly move troops from point to point and react with greater alacrity – belonged to the French defenders. Moreover, just as the German logistical train was being stretched to the breaking point, the French still enjoyed access to their own railways, only further enhancing their interior lines advantage.[xxv] France and its allies also enjoyed a clear quantitative advantage at this point in the war, as Moltke’s redeployment to the east meant that German forces, now numbering twenty divisions with a combined 750,000, faced combined French and British forces of over a million men.[xxvi]
On 29 August, Moltke ordered his army to advance south, ignoring Paris to encircle and crush French forces around Alsace-Lorraine. However, von Kluck’s First Army had advanced too aggressively, leaving a gap between the First and Second Army vulnerable to attack from French forces in Paris. With only one reserve corps guarding the German right flank, Joffre unleashed the French Sixth Army on the Germans, crashing into the exposed right wing of the German Second Army and tearing a 40km gap in the German lines. The BEF then plunged into this hole, effectively cutting off the German First Army from the rest of the front and menacing the rear of the German Second Army.[xxvii] On September 9, the fortieth day of the conflict and the point by which the Schlieffen Plan had assumed French capitulation to be imminent, Moltke ordered German forces to retreat behind the Aisne River.[xxviii] This decision marked the end of the opening offensive and the ultimate failure of the Schlieffen Plan.
Considering the Merits and Demerits of the Schlieffen Plan
Before advancing into the analysis, it is important to note one thing clearly: The Schlieffen Plan was a failure both operationally and strategically. It did not eliminate France from the war, it assured British entry into the conflict, and it did not succeed in annihilating the French Army as Moltke had hoped. In that sense, one cannot objectively argue that the Schlieffen Plan accomplished its objectives. Despite these operational and strategic shortfalls, however, the Schlieffen Plan was not an abject failure for two reasons. First, it allowed Germany to occupy the industry and resource-rich northeast of France. By pushing the French back, it also protected the crucial region of the Saarland, which was home to a large segment of German heavy industry needed to support the war effort. Nonetheless, these achievements were more than outweighed by the strategic debacle created by the entry of the U.K., which led to a greater number of soldiers facing down the German military and, more importantly, the imposition of a complete blockade of Germany that strangled its war effort.
The failure of the plan is attributable to three fundamental shortcomings in the manner in which it was created. First, the German General Staff enjoyed nearly complete autonomy to plan as it saw appropriate. While this approach, divorced from political fetters and mismanagement, contributed to the stunning German success at the outset of the campaign in France, it also led to a failure to adequately recognize and grasp the grand strategic implications of German action. For example, despite clear British warnings that a violation of Belgian neutrality would guarantee their entry into the war, the German General Staff never fully appreciated the consequences of their turn through Belgium.[xxix] In other words, in an effort to win a quick victory over the French, German military leadership ensured that they would face a much more difficult war if they proved unable to quickly knock the French out of the campaign. The automaticity of the plan also limited Germany’s strategic options. Because German strategy relied on rapid mobilization, once the country began to follow a path toward war there was nothing the political leadership could do to halt the Army’s deployment to the west. This effectively barred civilian leadership from the decision process and even undermined peace talks that were underway between Paris, Vienna, and St. Petersburg by forcing a rapid military escalation irrespective of the political situation.[xxx]
Second, the German General Staff utterly failed to coordinate with its Austro-Hungarian counterparts. Indeed, the extent of joint planning was the annual exchange of Christmas cards during the holidays.[xxxi] This inability to recognize the importance of alliance partners proved extremely detrimental to German interests, as it led to a bizarre situation in which the entire Eastern Front was left all but defenseless to Russian attack. This was deeply troubling to Moltke, as the Germans were counting on an Austro-Hungarian offensive against Russia to buy them the time needed to defeat France, deploying only 10% of their forces to the east. The Austro-Hungarian Galician front was equally sparse, as Austrian Chief of Staff Conrad von Hötzendorf inexplicably decided to activate War Case B, a plan that directed the entire military against Serbia despite the growing Russian menace in the east. While von Hötzendorf belatedly attempted to switch to War Case B+R, which would have deployed a sizeable number of forces to Galicia in the east, the railroad system and mobilization timetables were too rigid to adjust to this change, and Austro-Hungarian troops went on, what Alexander Watson calls a “[1,000km] joyride to the Balkans.”[xxxii] While the Germans were able to defeat the Russians at Tannenberg in East Prussia, thus securing the eastern front against imminent Russian invasion, this was largely due to luck that Moltke could not have foreseen.[xxxiii] The extremely slow Austro-Hungarian mobilization to the east, in large part attributable to a lack of close coordination and war-planning between Berlin and Vienna, did not occur until late in August.[xxxiv] Thus, little stood in the way of the Russian Army, and concern over the undefended east compelled Moltke to prematurely shift forces from France. As a result, Germany simply lacked the depth necessary to halt the counterattack of the French Sixth Army and lost the small degree of momentum its forces had achieved in France.
Third, the Schlieffen Plan assumed a tactical and numerical superiority that Germany simply did not possess. While the campaign against France assumed an army of 94 divisions in the west, the Kaiser’s forces in 1914 could array only 60 divisions against the French.[xxxv] The Germans were, quite simply, fighting with phantom divisions. This became painfully apparent as the German Army became increasingly overextended as it advanced along an ever wider front and occupied regions with restive populations. The shortage in available forces was only exacerbated by a failure to account for logistical hurdles. From a lack of automobiles to an underestimation of the extent of Belgian railroad sabotage, the German General Staff consistently and systematically downplayed the problems associated with supplying such a massive force. As a result, units bogged down and were unable to exploit operational openings quickly enough to have a strategic effect. Finally, the General Staff had an almost racist view of the French, whose Republican traditions they deemed inferior to German authoritarian discipline, and they complacently assumed a near-repeat of the 1871 victory in the Franco-Prussian War.[xxxvi]
It is perhaps possible that German forces could have overcome these barriers to success if they were simply much better than the French forces that opposed them. Indeed, this was part of the myth German leaders told themselves to justify such a risky gamble. The reality was far more complex. While the German Army was clearly the most proficient of the Continental forces – with more rigorous training and a greater number of experienced NCOs per company – its advantage in armaments was very slight.[xxxvii] The Germans had about 500 more heavy field guns than the French, and their howitzers had no equivalent in the French inventory. However, French field artillery was more effective, with greater range, firepower, and rate of fire. France also enjoyed a slight advantage in aircraft. In all other indicators, the armies were almost exactly on an equal footing.[xxxviii] Therefore, German convictions that a quick victory was possible were little more than naïve optimism. Of course, this also means that those who blame Moltke for “diluting” Schlieffen’s initial plan are unfair in their criticism. It was not Moltke’s “weakening” of the right wing that proved consequential. Rather, Germany simply lacked the necessary number of divisions needed to execute an invasion of this scale and magnitude. Moltke’s adaptations, moreover, likely did much to salvage the plan, as they recognized certain political realities – such as the need to bolster defenses against a French attack on Alsace-Lorraine – and kept German forces out of Holland, thus reducing the size of the front and level of manpower needed to hold occupied territory.
The Schlieffen Plan was a bold idea for solving an intractable problem. The campaign envisaged by the Schlieffen Plan made perfect sense on an abstract level, as it allowed Germany to achieve local superiority against the French, eliminate the threat in the west, and then concentrate the full might of the German Army against the Russians. Moreover, it adroitly recognized the advantages provided by internal lines and railroads, planning to exploit them for the rapid transfer of troops from front to front. However, the Schlieffen Plan failed to account for the operational challenges that would surface in France. By exaggerating German tactical prowess, underestimating Belgian resolve, and ignoring the logistical headaches that would be created by the deployment of hundreds of thousands on foreign soil, the Germans created a Pollyannaish plan. These errors were compounded by the fact that decision-making rested almost entirely within the General Staff, leading to important grand strategic oversights and a failure to coordinate with allies. As a result, the campaign pulled the powerful British Empire into the war against the Germans and left the Eastern Front almost completely exposed. Thus, while the campaign realized some important successes, it failed to achieve its initial objectives. Germany found itself bogged down in the west as its forces slowly wore down and its economy suffocated under the strangulation of the British blockade. The German General Staff thought big, and they came tantalizingly close to victory. To their detriment, though, their early successes were not big enough, and they found themselves in an awful war of attrition that ultimately led to the collapse of their empire.
[i] David Stone, The Kaiser’s Army (London, U.K.: Conway Bloomsbury, 2015), 40.
[ii] Ibid., 40.
[iii] Alexander Watson, Ring of Steel: Germany and Austria-Hungary in World War I (New York, N.Y.: Basic Books, 2014), 106.
[iv] Christopher Clark, The Sleepwalkers: How Europe Went to War in 1914 (New York, N.Y.: Harper Perennial, 2012), 123.
[v] Ibid., 123.
[vi] Watson, 104.
[vii] Stone, 41-42.
[viii] Watson, 106-107.
[ix] James Joll and Gordon Martel, The Origins of the First World War (London, U.K.: Pearson, 2007), 15.
[x] Ibid., 19.
[xi] Ibid., 21.
[xii] Ibid., 35-36.
[xiii] Jörn Leonhard, Pandora’s Box: A History of the First World War (Cambridge, Mass.: Belknap, 2018), 143.
[xiv] David Stevenson, Cataclysm: The First World War as Political Tragedy (New York, N.Y.: Basic Books, 2004), 43.
[xv] Leonhard, 148.
[xvi] Dennis Showalter, Instrument of War (Oxford, U.K.: Osprey, 2016), 54.
[xvii] Ibid., 58.
[xviii] Watson, 129-133.
[xix] Stevenson, 44.
[xx] Ibid., 45.
[xxii] Stone, 43.
[xxiii] Stevenson, 45.
[xxiv] Ibid., 46.
[xxv] Watson, 134.
[xxvi] Leonhard, 157.
[xxvii] Watson, 135.
[xxviii] Stone, 61.
[xxix] Joll & Martel, 37.
[xxx] Fritz Fischer, “The Foreign Policy of Imperial Germany and the Outbreak of World War One,” in Escape into War? edited by Schöilgen, 35, Oxford, U.K.: Berg, 1990.
[xxxi] Watson, 105.
[xxxii] Ibid., 138.
[xxxiii] Stone, 70-72.
[xxxiv] Stevenson, 57.
[xxxv] Stone, 42.
[xxxvi] Watson, 111.
[xxxvii] Ibid., 111-112.
[xxxviii] Ibid., 108.
Clark, Christopher. The Sleepwalkers: How Europe Went to War in 1914. New York, N.Y.: Harper Perennial, 2012.
Fischer, Fritz. “The Foreign Policy of Imperial Germany and the Outbreak of World War One” in Escape into War? edited by Schöilgen, 19-40. Oxford, U.K.: Berg, 1990.
Joll, James and Gordon Martel, The Origins of the First World War. London, U.K.: Pearson, 2007.
Leonhard, Jörn. Pandora’s Box: A History of the First World War. Cambridge, Mass.: Belknap, 2018.
“Northwest Europe, 1914 – Allied Retreat, 30 August – 5 September,” in Campaign Atlas to The Great War. U.S. Army War College History Department. Accessed Nov. 5, 2018. https://www.westpoint.edu/history/SitePages/WWI.aspx.
“Northwest Europe, 1914 – German Withdrawal to the Aisne and Stabilization of the Front,” in Campaign Atlas to The Great War. U.S. Army War College History Department. Accessed Nov. 5, 2018. https://www.westpoint.edu/history/SitePages/WWI.aspx.
“Northwest Europe, 1914, Western Front, The Schlieffen Plan and the French Plan,” in Campaign Atlas to The Great War. U.S. Army War College History Department. Accessed Nov. 5, 2018. https://www.westpoint.edu/history/SitePages/WWI.aspx.
Stevenson, David. Cataclysm: The First World War as Political Tragedy. New York, N.Y.: Basic Books, 2004.
Stone, David. The Kaiser’s Army. London, U.K.: Conway Bloomsbury, 2015.
Showalter, Dennis. Instrument of War. Oxford, U.K.: Osprey, 2016.
Watson, Alexander. Ring of Steel: Germany and Austria-Hungary in World War I. New York, N.Y.: Basic Books, 2014.