This document originally appeared on the Houghton Mifflin Company college division website at

This webpage went down in August 2006, so I have copied it here.


This document was written by and is therefore copyright the American military historian Dennis E. Showalter.

Reader's Companion to Military History

World War I


World War I was the defining event of the twentieth century. Its unfinished political and military business laid the foundation for an even greater world war that began in 1939. Its impact on the great powers of Europe cleared the ground for the peripheral empires, the United States and the USSR, which in turn engaged in a third world war, a cold one, that ended only in 1989. World War I marked the beginning of the end of Europe's moral and material hegemony over the world. It heralded the rise of managed economies. It opened the way to a technological revolution focused on electronics and internal combustion engines.

These and all the other results of the Great War were unintended consequences. Tensions among Europe's major powers long antedated the actual outbreak of hostilities in 1914. War was not only expected: by the turn of the twentieth century, it was even desired in certain circles. The war's origins reflected economic and imperial rivalries and alliance systems that encouraged mutual belligerence. In that environment, rational calculation might reasonably accept war as the best feasible alternative to a state's political and military problems. Germany in particular believed by 1914 that a bid for continental hegemony and world power had a good chance of success. Germany's ally Austria-Hungary saw its survival contingent on destroying the South Slavic nationalism embodied in Serbia. The entente powers, France, Britain, and Russia, in turn decided that Germany could be stopped at reasonable cost. War thus became the continuation of politics by other means. The assassination of Hapsburg archduke Franz Ferdinand on June 28, 1914, in the Bosnian city of Sarajevo provided an excuse to settle fundamental issues of European politics.

World War I was also in part an accident. International rivalries were no worse in 1914 than in earlier years. Instead a generation of mediocre statesmen and second-rate soldiers proved unable to control the events that helped generate the crisis that followed the assassination. Indeed, worried about a belligerent public, they may have been less frightened of making war than of not making war. In a matter of days, from August 1 to August 4, the Central Powers (Germany and Austria-Hungary) and the Triple Entente (France, Russia, and Britain) sprang at each other's throats.

The participants agreed that the conflict would be short. Despite their differences, the great powers had enough in common socially, politically, and economically that the Great War at least began as a civil war rather than a mutual struggle for survival. Exponential increases in the destructive power of modern weapons were accompanied by a widespread belief that modern societies and modern psyches were too fragile to sustain the strain of war for any length of time. Commitment of Europe's armies to all-out strategic and tactical offensives were based on the premise that the war had to be won quickly or not at all.

But Germany's Schlieffen Plan, the French Plan XVII, Austria-Hungary's invasions of Russia and Serbia, and Russia's two-pronged drive into Galicia and East Prussia all produced casualties on scales unknown in Western civilization. Almost 150,000 Russians were lost in the Battle of Tannenberg alone. French and German casualties in the war's first four months each exceeded 800,000. By year's end Russian troops had penetrated deeply into Austria-Hungary. Most of Belgium and much of northeastern France were in German hands. The conquests, however, were inconvenient: they were too small to convince the losers that there was no alternative to making peace, and too large to risk negotiation without making an effort to recover them by force.

The generals learned much between August and December of 1914. Railroad networks enabled the rapid movement of large forces over long distances, but once out of boxcars, soldiers still moved at foot speed. This fact by itself limited the impact of success since reserves could block breakthroughs faster than any momentary advantage could be exploited. Nor were victories easily won. Firepower had been gridlocking battlefields since the final years of the wars of Napoleon. Magazine rifles, automatic machine guns, and rapid-firing field and heavy artillery gave the defense an advantage unknown in the history of warfare. The year 1914 introduced a new aspect to the problem. The sheer size of modern armies created force-to-space ratios so high that even in the wider reaches of eastern Europe, maneuver became almost impossible. Open enemy flanks could not be enveloped because they either did not exist or did not remain open for long. Nor did soldiers continue to stand heroically upright and charge forward with bayonets fixed. Instead they dug. By December 1914, a line of trenches no less formidable for being improvised defined the Western Front from the Swiss border to the English Channel, a distance of 470 miles. In the east, defensive systems were less comprehensive—because the front ran for almost double the distance—but proved almost as successful in defying attacks. Moreover, the avoidance of stalemate called for levels of genius foreign to the soldiers and the statesmen responsible for the war's direction.

The entente powers possessed a significant advantage in the resource race. Their control of the seas enabled them to draw on the entire globe, whereas Germany and Austria-Hungary were denied access to anything but their immediate conquests. The discrepancy, however, must not be exaggerated. Europe was still the focal point of the world's industrial system. Even the United States supplied more raw materials than finished goods to its French and British customers. In 1915 and for months to come, national mobilization primarily involved for all the combatants utilizing and developing their internal resources.

The question was, how could these resources best be used? Germany and Austria-Hungary, like poker players with a big stack of winning chips, were in a position to stand pat. During 1915 the Central Powers did seek to remove Russia from the war by diplomatic and military means. They inflicted over a million casualties and advanced up to three hundred miles—but Russia refused to give up. The moribund tsarist government could not afford the risks of making a separate peace.

France and Britain faced three more immediate dilemmas. The French army and the French government were committed to recovering their occupied territory as quickly as possible. At the same time Russia was making increasing demands for support from its allies, as much for morale purposes as from material need. Finally, Britain, which had initially hoped to limit its continental commitments, found itself constrained instead to raise the first mass army in its history, albeit through volunteering rather than conscription, to match the French commitment to the stalemated Western Front.

The next question concerned how best to employ this force. Throughout 1915 the French dashed their army to pieces in a series of attacks on increasingly sophisticated German trench systems. Their demand that Britain participate in the process was accepted by a British high command that believed the only way to end the war was to smash the German army in a direct confrontation. Their decision would condemn sixty thousand men to death or maiming in the autumn Battle of Loos. As casualties mounted, however, the search for a way around intensified. Winston Churchill, then first lord of the Admiralty, argued forcefully, and convincingly, for an attack on the Dardanelles (see Gallipoli Campaign). This operation, directed against a ramshackle Ottoman Empire that had joined the Central Powers unenthusiastically in November 1914, would open a supply route to Russia, give the Allies a strong position in the Balkans, and convince Italy to enter the war in return for generous promises of territorial gains after the Central Powers' defeat.

It all seemed too good to be true—and was. The Anglo-French expedition bogged down on the Gallipoli Peninsula partly because of failures at high command levels, but also because of impassable terrain and unexpectedly effective Turkish resistance. The Allies suffered over a half million casualties before finally evacuating the survivors in December 1915. The Italian government, which had declared neutrality in 1914, finally joined the Allies despite substantial popular opposition in return for the promise of territory in the Adriatic Basin and the eastern Mediterranean. The Alps, however, proved a formidable obstacle to an inefficient Italian army that in 1917 was fighting no less than the Eleventh Battle of the Isonzo River !

By 1916, in short, the Great War was everywhere stalemated. Germany's colonies, with the exception of East Africa, were in Allied hands. Germany's principal overseas naval force had been destroyed off the Falklands in December 1914. But these were mere pinpricks. In the aftermath of the Dardanelles fiasco another British expeditionary force bogged down in Mesopotamia. The Turks surrounded ten thousand men of the Indian army at Kut and, after the longest siege in British history, forced them to surrender. An Anglo-French expeditionary force sent to the Balkans found itself so hemmed in around Salonika that the city was sarcastically dubbed the war's biggest internment camp. The civil war might have become a world war, but its focus remained in Europe.

With subtlety discredited, the major combatants again proposed to end the war by direct methods. Germany's chief of staff, Erich von Falkenhayn, proposed to draw the French army into a killing ground around the old fortress of Verdun, trading lives for lives until France was "bled white." Meanwhile, France and Britain planned a joint offensive along the Somme River—an offensive whose burden would be increasingly borne by the newly raised British armies. Both operations ended in mutual disaster. At Verdun, French and German losses totaled nearly 1.25 million, yet the lines in December 1916 remained almost where they had been when the German offensive began on February 21. The Somme offensive, lasting from July 1 to mid-November, gained a strip of territory about twenty miles wide and six miles deep at the price of 420,000 British casualties and, often overlooked, 200,000 French. German casualty figures remain debated, but seem to have approached almost 500,000.

By the year's end French manpower resources were at the edge of exhaustion. The enthusiasm of Britain's volunteers was giving way to resignation and cynicism. The German army's superb cadre of regular officers and NCOs had been virtually destroyed: the Somme, one officer wrote, became "the muddy grave of the German field army." Yet this general war-weariness did not generate a will to end killing that had by now become a mechanical process. Efforts to initiate peace negotiations proved futile, not least because by this time all the combatants had set the stakes so high and suffered such huge losses that no one was willing to talk. It is often overlooked that Europe's upper classes sacrificed their own sons to a degree unknown before or since. Generals and statesmen were also grieving fathers who could not accept the argument that their children had died for nothing.

Instead, the combatants sought to increase the scale of the fighting. By 1916 thousands of guns firing millions of shells formed a necessary part of any attack. Battalions that had begun the war with two machine guns now had six, nine, or twelve. When sheer weight of metal did not produce decision, the combatants took to technical innovation. On the ground, poison gas and armored fighting vehicles took the field, yet neither could break the tactical stalemate. Above the trenches, aviation technology developed exponentially after August 1914, but the wire-and-strut biplanes were still too limited in their capacities by 1918 to be more than a limited auxiliary to the ground forces. At sea, the battle fleets built at such cost spent most of their time in harbor, occasionally emerging to engage in arm's-length duels like the Battle of Jutland on May 31, 1916, but never taking serious risks. This caution had psychological as well as military roots. When Winston Churchill called Grand Fleet commander Sir John Jellicoe the only man who could lose the war in an afternoon, he was recognizing that warships had become not merely fighting entities but symbols of their respective states.

The Allied blockade was inflicting increasing hardship on the Central Powers. Germany especially suffered the domestic consequences of exponentially declining living standards during 1916. But to seek victory through slow strangulation invited the question of whether the Allies might not crack first. Even as Verdun and the Somme raged in the summer of 1916, Russia mounted an offensive that produced significant initial gains but then, like all of its predecessors on every front, bogged down. In March 1917, the tsarist government gave way to a republic. Its premier, Alexander Kerensky, promised continued commitment to the war. Whether he could transform words to deeds was at best questionable.

Then, from across the Atlantic, a new hope emerged. The United States had initially sought to remain, in President Woodrow Wilson's words, "neutral in thought, word, and deed." However, a combination of emotional sympathy for the Allied cause, close economic ties with France and Britain, and clumsy German diplomacy convinced increasing numbers of Americans from the White House downward that a German victory would eventually prove disastrous for U.S. interests. Any lingering doubts were removed in January 1917, when Germany announced a policy of unrestricted submarine warfare, sinking any ship under any flag that approached the British Isles. In April, the United States declared war.

Seen in hindsight, the German decision seems a fecklessly applied recipe for disaster. In German terms it was a calculated risk. The United States possessed neither a balanced fleet nor a strong army. Even if the Americans could create a credible land force, German experts dismissed the possibility that it could be transported across the Atlantic at all, much less in time to save Britain from strangulation and France from itself.

Germany's prospects for victory seemed to increase as French and British offensives undertaken on the Western Front in 1917 proved more indecisive than Verdun and the Somme. In April 1917, the French army suffered such a one-sided disaster on the ridges of the Chemin des Dames that its hard-tried poilus mutinied. In the fall it was Britain's turn, as division after division vanished into the gelatinous mud of Flanders. The British Expeditionary Force lost another quarter million men in exchange for a few thousand yards of shell-churned ground and the ruined village of Passchendaele. German losses were almost as heavy. It was nevertheless clear that German defensive systems had become too complex, and German defensive tactics too sophisticated, to yield readily either to brute force or finesse. In the words of the new French field commander, Philippe Pétain, it was necessary to wait for the Americans and the tanks.

But would either arrive in time to prevent Germany from springing through what seemed a final window of opportunity? Well before Lenin's Bolsheviks gave it the coup de grâce in November 1917, Kerensky's government was disintegrating. A Germany by now completely dominated by its generals saw this as an opportunity to create an eastern European sphere of influence impervious to blockade—an empire that would restore at least the material losses suffered since 1914. Troops poured eastward to occupy territories in Poland, the Ukraine, even Finland. But the process of acquiring and exploiting the new territories would take time, and time was something Germany no longer possessed.

In October 1917, a joint German-Austrian offensive shattered the Italian army at Caporetto, inflicting 600,000 casualties—half of whom simply deserted. But once again this tactical victory produced no political gains; Italy remained in the war. Enough resources remained for one last blow. The German high command decided on a series of tactically focused attacks designed to split the French and British armies on the Western Front. Perhaps the British might retreat to the seacoast. France might consider peace on German terms. At worst, Erich Ludendorff expected so to cripple his adversaries that Germany would have time to consolidate its new continental position.

Hopes in this regard were enhanced when on March 3, 1918, a Bolshevik government concluded at Brest-Litovsk a treaty that gave Germany hegemony in central Europe. Eighteen days later, the German western offensive began. Employing innovative systems of artillery fire control combined with infantry tactics based on bypassing enemy strong points, Ludendorff's March 21 attack achieved initial successes that gave the Allies the courage of desperation (see Ludendorff Offensive). An April offensive against the British on the Lys River was briefly more threatening. For the first time the entente accepted a supreme commander. Marshal Ferdinand Foch proved more a coordinator than a generalissimo. Nevertheless, he was able to secure higher levels of mutual cooperation than had previously been the case—a particularly important factor given the insistence of the Americans that their rapidly growing army play an independent role in the war.

Meanwhile the German drive was coming to a standstill, as much from physical and moral exhaustion as from Allied countermeasures. By June the front had stabilized. In July the Allies counterattacked. First it was the turn of the tanks. At Soissons, exhausted French infantrymen—and American reinforcements—followed the increasing numbers of armored vehicles into German positions. On August 8, the British army used its armor to rip open the German lines around Amiens. By this time the British had learned how to combine fire and movement in set-piece attacks that followed each other so closely that an exhausted German army had no time to counterstrike or rally.

Meanwhile the Americans had taken the field. The U-boats had been unable to stop their flow across the Atlantic. By July 1918 over a million American troops were on European soil with hundreds of thousands more arriving each month. In September, with French help, the American First Army pinched off the St.-Mihiel salient. In October it embarked on an offensive against far more formidable positions in the Argonne Forest. Clumsy tactics, poor commanders, and sheer inexperience led to high casualties, but the Americans' will and enthusiasm were the final blows to a German army that had long since exhausted both qualities. With defeat staring him in the face, Ludendorff called for peace. For a few days Germany had for the first time in its history a parliamentary government. Then a wave of revolt swept the country. Kaiser Wilhelm II abdicated. His senior generals sought retirement, leaving the newly established Weimar Republic to face a victors' coalition neither willing nor able to be generous in its days of triumph.

At 11:00 a.m. on November 11, 1918, the guns fell silent. About nine million men in uniform had perished. Millions of other human beings would die in an influenza pandemic whose impact owed much to the physical and emotional effects of a war that left Europe in shambles. The success of the Bolshevik Revolution, impossible without the war, drew an ideological line of demarcation between the new Soviet Union and its neighbors. The territorial changes in central Europe, largely a consequence of Austria-Hungary's dissolution, created a network of weak, unstable states. The Treaty of Versailles, with its territorial, economic, and military demands, was widely viewed by Germans as imposing intolerable, immoral burdens on a country that had fought in self-defense. Adolf Hitler's promises to expunge the "disgrace" of 1918 contributed significantly to his rise to power—and to the launching in 1939 of a second war for the mastery of Europe.

Since the Great War, Europe has had neither the will nor the means to sustain the process of expanding its world influence that had begun in the fifteenth century. The mutual destruction that began in August 1914 continues to cast its shadow.