Developments in 1917
Events of 1917 proved decisive in ending the war, although their effects were not fully felt until 1918.
The British naval blockade began to have a serious impact on Germany. In response, in February 1917, the German General Staff convinced Chancellor Theobald von Bethmann-Hollweg to declare unrestricted submarine warfare, with the goal of starving Britain out of the war. German planners estimated that unrestricted submarine warfare would cost Britain a monthly shipping loss of 600,000 tons. While it was realised that the policy was also likely to bring the United States into the conflict, British shipping losses would be so high that it would be forced to sue for peace after 5 to 6 months, before American intervention could make an impact. In reality, tonnage sunk rose above 500,000 tons per month from February to July. It peaked at 860,000 tons in April. After July, the newly re-introduced convoy system became extremely effective in reducing the U-boat threat. Britain was safe from starvation while German industrial output fell, and the United States troops joined the war in large numbers far earlier than Germany had anticipated.
On 3 May 1917, during the Nivelle Offensive, the weary French 2nd Colonial Division, veterans of the Battle of Verdun, refused their orders, arriving drunk and without their weapons. Their officers lacked the means to punish an entire division, and harsh measures were not immediately implemented. Then, mutinies afflicted an additional 54 French divisions and saw 20,000 men desert. The other Allied forces attacked but sustained tremendous casualties. However, appeals to patriotism and duty, as well as mass arrests and trials, encouraged the soldiers to return to defend their trenches, although the French soldiers refused to participate in further offensive action. Robert Nivelle was removed from command by 15 May, replaced by General Philippe Pétain, who suspended bloody large-scale attacks.
The victory of Austria–Hungary and Germany at the Battle of Caporetto led the Allies at the Rapallo Conference to form the Supreme War Council to coordinate planning. Previously, British and French armies had operated under separate commands.
In December, the Central Powers signed an armistice with Russia. This released large numbers of German troops for use in the west. With German reinforcements and new American troops pouring in, the outcome was to be decided on the Western front. The Central Powers knew that they could not win a protracted war, but they held high hopes for success based on a final quick offensive. Furthermore, the leaders of the Central Powers and the Allies became increasingly fearful of social unrest and revolution in Europe. Thus, both sides urgently sought a decisive victory.
Entry of the United States
The United States originally pursued a policy of non-intervention, avoiding conflict while trying to broker a peace. When a German U-boat sank the British liner Lusitania in 1915, with 128 Americans aboard, U.S. President Woodrow Wilson vowed, "America is too proud to fight" and demanded an end to attacks on passenger ships. Germany complied. Wilson unsuccessfully tried to mediate a settlement. He repeatedly warned the U.S. would not tolerate unrestricted submarine warfare, in violation of international law and U.S. ideas of human rights. Wilson was under pressure from former president Theodore Roosevelt, who denounced German acts as "piracy". Wilson's desire to have a seat at negotiations at war's end to advance theLeague of Nations also played a role. Wilson's Secretary of State, William Jennings Bryan, whose opinions had been ignored, resigned as he could no longer support the president's policy. Public opinion was angered at suspected German sabotage of Black Tom in Jersey City, New Jersey, and the Kingsland Explosion.
In January 1917, Germany resumed unrestricted submarine warfare. The German Foreign minister, in the Zimmermann Telegram, told Mexico that U.S. entry was likely once unrestricted submarine warfare began, and invited Mexico to join the war as Germany's ally against the United States. In return, the Germans would send Mexico money and help it recover the territories of Texas, New Mexico, and Arizona that Mexico lost during the Mexican-American War 70 years earlier. Wilson released the Zimmerman note to the public and Americans saw it as a casus belli—a cause for war.
U.S. declaration of war on Germany
First active U.S. participationAfter the sinking of seven U.S. merchant ships by submarines and the publication of the Zimmerman telegram, Wilson called for war on Germany, which the U.S. Congress declared on 6 April 1917.
The United States was never formally a member of the Allies but became a self-styled "Associated Power". The United States had a small army, but, after the passage of the Selective Service Act, it drafted 2.8 million men and by summer 1918 was sending 10,000 fresh soldiers to France every day. In 1917, the U.S. Congress gave U.S. citizenship to Puerto Ricans when they were drafted to participate in World War I, as part of the Jones Act. Germany had miscalculated, believing it would be many more months before they would arrive and that the arrival could be stopped by U-boats.
The United States Navy sent a battleship group to Scapa Flow to join with the British Grand Fleet, destroyers to Queenstown, Ireland and submarines to help guard convoys. Several regiments of U.S. Marines were also dispatched to France. The British and French wanted U.S. units used to reinforce their troops already on the battle lines and not waste scarce shipping on bringing over supplies. The U.S. rejected the first proposition and accepted the second. General John J. Pershing, American Expeditionary Forces (AEF) commander, refused to break up U.S. units to be used as reinforcements for British Empire and French units. As an exception, he did allow African-American combat regiments to be used in French divisions. The Harlem Hellfighters fought as part of the French 16th Division, earning a unit Croix de guerre for their actions at Chateau-Thierry, Belleau Wood and Sechault. AEF doctrine called for the use of frontal assaults, which had long since been discarded by British Empire and French commanders because of the large loss of life.
Austrian offer of separate peace
In 1917, Emperor Charles I of Austria secretly attempted separate peace negotiations with Clemenceau, with his wife's brother Sixtus in Belgium as an intermediary, without the knowledge of Germany. When the negotiations failed, his attempt was revealed to Germany, resulting in a diplomatic catastrophe.
German Spring Offensive of 1918
German General Erich Ludendorff drew up plans (codenamed Operation Michael) for the 1918 offensive on the Western Front. The Spring Offensive sought to divide the British and French forces with a series of feints and advances. The German leadership hoped to strike a decisive blow before significant U.S. forces arrived. The operation commenced on 21 March 1918 with an attack on British forces near Amiens. German forces achieved an unprecedented advance of 60 kilometres (40 miles).
British and French trenches were penetrated using novel infiltration tactics, also named Hutier tactics, after General Oskar von Hutier. Previously, attacks had been characterised by long artillery bombardments and massed assaults. However, in the Spring Offensive of 1918, Ludendorff used artillery only briefly and infiltrated small groups of infantry at weak points. They attacked command and logistics areas and bypassed points of serious resistance. More heavily armed infantry then destroyed these isolated positions. German success relied greatly on the element of surprise.
The front moved to within 120 kilometres (75 mi) of Paris. Three heavy Krupp railway guns fired 183 shells on the capital, causing many Parisians to flee. The initial offensive was so successful that Kaiser Wilhelm II declared 24 March a national holiday. Many Germans thought victory was near. After heavy fighting, however, the offensive was halted. Lacking tanks or motorised artillery, the Germans were unable to consolidate their gains. This situation was not helped by the supply lines now being stretched as a result of their advance. The sudden stop was also a result of the four Australian Imperial Force (AIF) divisions that were "rushed" down, thus doing what no other army had done and stopping the German advance in its tracks. During that time the first Australian division was hurriedly sent north again to stop the second German breakthrough.
General Foch pressed to use the arriving American troops as individual replacements. Pershing sought instead to field American units as an independent force. These units were assigned to the depleted French and British Empire commands on 28 March. A Supreme War Council of Allied forces was created at the Doullens Conference on 5 November 1917. General Foch was appointed as supreme commander of the allied forces. Haig, Petain and Pershing retained tactical control of their respective armies; Foch assumed a coordinating role, rather than a directing role and the British, French and U.S. commands operated largely independently.
Following Operation Michael, Germany launched Operation Georgette against the northern English Channel ports. The Allies halted the drive with limited territorial gains for Germany. The German Army to the south then conducted Operations Blücher and Yorck, broadly towards Paris. Operation Marne was launched on 15 July, attempting to encircle Reims and beginning the Second Battle of the Marne. The resulting counterattack, starting the Hundred Days Offensive, marked their first successful Allied offensive of the war.
By 20 July the Germans were back across the Marne at their Kaiserschlacht starting lines, having achieved nothing. Following this last phase of the war in the West, the German Army never again regained the initiative. German casualties between March and April 1918 were 270,000, including many highly trained stormtroopers.
Meanwhile, Germany was falling apart at home. Anti-war marches became frequent and morale in the army fell. Industrial output was 53 percent of 1913 levels.
New states under war zone
In 1918, the internationally recognized Azerbaijan Democratic Republic, Democratic Republic of Armenia and Democratic Republic of Georgia bordering the Ottoman Empire and Russian Empire were established, as well as the unrecognized Centrocaspian Dictatorship and South West Caucasian Republic. Later, these unrecognized states were eliminated by Azerbaijan and Turkey.
In 1918, the Dashnaks of the Armenian national liberation movement declared the Democratic Republic of Armenia (DRA) through the Armenian Congress of Eastern Armenians (unified form of Armenian National Councils) after the dissolution of the Transcaucasian Democratic Federative Republic. Tovmas Nazarbekian became the first Commander-in-chief of the DRA. Enver Pasha ordered the creation of a new army to be named the Army of Islam. He ordered the Army of Islam into the DRA, with the goal of taking Baku on the Caspian Sea. This new offensive was strongly opposed by the Germans. In early May 1918, the Ottoman army attacked the newly declared DRA. Although the Armenians managed to inflict one defeat on the Ottomans at the Battle of Sardarabad, the Ottoman army won a later battle and scattered the Armenian army. The Republic of Armenia signed the Treaty of Batum in June 1918.
Allied victory: summer and autumn 1918
The Allied counteroffensive, known as the Hundred Days Offensive, began on 8 August 1918. The Battle of Amiens developed with III Corps British Fourth Army on the left, the French First Army on the right, and theAustralian and Canadian Corps spearheading the offensive in the centre through Harbonnières. It involved 414 tanks of the Mark IV and Mark V type, and 120,000 men. They advanced 12 kilometres (7 miles) into German-held territory in just seven hours. Erich Ludendorff referred to this day as the "Black Day of the German army".
The Australian-Canadian spearhead at Amiens, a battle that was the beginning of Germany’s downfall, helped pull the British armies to the north and the French armies to the south forward. While German resistance on the British Fourth Army front at Amiens stiffened, after an advance as far as 14 miles (23 km) and concluded the battle there, the French Third Army lengthened the Amiens front on 10 August, when it was thrown in on the right of the French First Army, and advanced 4 miles (6 km) liberating Lassigny in fighting which lasted until 16 August. South of the French Third Army, General Charles Mangin (The Butcher) drove his French Tenth Army forward at Soissons on 20 August to capture eight thousand prisoners, two hundred guns and the Aisne heights overlooking and menacing the German position north of the Vesle.Another "Black day" as described by Erich Ludendorff.
Meanwhile General Byng of the Third British Army, reporting that the enemy on his front was thinning in a limited withdrawal, was ordered to attack with 200 tanks towards Bapaume, opening the Battle of Albert, with the specific orders of "To break the enemy's front, in order to outflank the enemies present battle front" (opposite the British Fourth Army at Amiens). Allied leaders had now realised that to continue an attack after resistance had hardened was a waste of lives and it was better to turn a line than to try to roll over it. Attacks were being undertaken in quick order to take advantage of the successful advances on the flanks and then broken off when that attack lost its initial impetus.
The British Third Army's 15-mile (24 km) front north of Albert progressed after stalling for a day against the main resistance line to which the enemy had withdrawn. Rawlinson’s Fourth British Army was able to battle its left flank forward between Albert and the Somme straightening the line between the advanced positions of the Third Army and the Amiens front which resulted in recapturing Albert at the same time. On 26 August the British First Army on the left of the Third Army was drawn into the battle extending it northward to beyond Arras. The Canadian Corps already being back in the vanguard of the First Army fought their way from Arras eastward 5 miles (8 km) astride the heavily defended Arras-Cambrai before reaching the outer defences of the Hindenburg Line, breaching them on the 28 and 29 August. Bapaume fell on the 29 August to the New Zealand Division of the Third Army and the Australians, still leading the advance of the Fourth Army, were again able to push forward at Amiens to take Peronne and Mont Saint-Quentin on 31 August. Further south the French First and Third Armies had slowly fought forward while the Tenth Army, who had by now crossed the Ailette and was east of the Chemin des Dames, was now near to the Alberich position of the Hindenburg Line. During the last week of August the pressure along a 70-mile (113 km) front against the enemy was heavy and unrelenting. From German accounts, "Each day was spent in bloody fighting against an ever and again on-storming enemy, and nights passed without sleep in retirements to new lines." Even to the north in Flanders the British Second and Fifth Armies during August and September were able to make progress taking prisoners and positions that were previously denied them.
On 2 September the Canadian Corps outflanking of the Hindenburg line, with the breaching of the Wotan Position, made it possible for the Third Army to advance and sent repercussions all along the Western Front. That same day Oberste Heeresleitung (OHL) had no choice but to issue orders to six armies for withdrawal back into the Hindenburg Line in the south, behind the Canal du Nord on the Canadian-First Army's front and back to a line east of the Lys in the north, giving up without a fight the salient seized in the previous April.According to Ludendorff “We had to admit the necessity ... to withdraw the entire front from the Scarpe to the Vesle.”
In nearly four weeks of fighting since 8 August, over 100,000 German prisoners were taken, 75,000 by the BEF and the rest by the French. Since "The Black Day of the German Army" the German High Command realised the war was lost and made attempts for a satisfactory end. The day after the battle Ludenforff told Colonel Mertz "We cannot win the war any more, but we must not lose it either." On 11 August he offered his resignation to the Kaiser, who refused it and replied, "I see that we must strike a balance. We have nearly reached the limit of our powers of resistance. The war must be ended." On 13 August at Spa, Hindenburg, Ludendorff, Chancellor and Foreign Minister Hintz agreed that the war could not be ended militarily and on the following day the German Crown Council decided victory in the field was now most improbable. Austria and Hungary warned that they could only continue the war until December and Ludendorff recommended immediate peace negotiations, to which the Kaiser responded by instructing Hintz to seek the mediation of the Queen of the Netherlands. Prince Rupprecht warned Prince Max of Baden "Our military situation has deteriorated so rapidly that I no longer believe we can hold out over the winter; it is even possible that a catastrophe will come earlier." On 10 September Hindenburg urged peace moves to Emperor Charles of Austria and Germany appealed to the Netherlands for mediation. On the 14 September Austria sent a note to all belligerents and neutrals suggesting a meeting for peace talks on neutral soil and on 15 September Germany made a peace offer to Belgium. Both peace offers were rejected and on 24 September OHL informed the leaders in Berlin that armistice talks were inevitable.
September saw the Germans continuing to fight strong rear guard actions and launching numerous counter attacks on lost positions, with only a few succeeding and then only temporarily. Contested towns, villages, heights and trenches in the screening positions and outposts of the Hindenburg Line continued to fall to the Allies, with the BEF alone taking 30,441 prisoners in the last week of September. Further small advances eastward would follow the Third Army victory at Ivincourt on 12 September, the Fourth Armies at Epheny on 18 September and the French gain of Essigny-le-Grand a day later. On 24 September a final assault by both the British and French on a 4 mile (6 km) front would come within 2 miles (3 km) of St. Quentin. With the outposts and preliminary defensive lines of the Siegfried and Alberich Positions eliminated the Germans were now completely back in the Hindenburg Line. With the Wotan position of that line already breached and the Siegfried position in danger of being turned from the north the time had now come for an assault on the whole length of the line.
The Allied attack on the Hindenburg Line began on 26 September including U.S. soldiers. The still-green American troops suffered problems coping with supply trains for large units on a difficult landscape. The following week cooperating French and American units broke through in Champagne at the Battle of Blanc Mont Ridge, forcing the Germans off the commanding heights, and closing towards the Belgian frontier.The last Belgian town to be liberated before the armistice was Ghent, which the Germans held as a pivot until Allied artillery was brought up. The German army had to shorten its front and use the Dutch frontier as an anchor to fight rear-guard actions.
When Bulgaria signed a separate armistice on 29 September, the Allies gained control of Serbia and Greece. Ludendorff, having been under great stress for months, suffered something similar to a breakdown. It was evident that Germany could no longer mount a successful defence.
Meanwhile, news of Germany's impending military defeat spread throughout the German armed forces. The threat of mutiny was rife. Admiral Reinhard Scheer and Ludendorff decided to launch a last attempt to restore the "valour" of the German Navy. Knowing the government of Prince Maximilian of Baden would veto any such action, Ludendorff decided not to inform him. Nonetheless, word of the impending assault reached sailors at Kiel. Many rebelled and were arrested, refusing to be part of a naval offensive which they believed to be suicidal. Ludendorff took the blame—the Kaiser dismissed him on 26 October. The collapse of the Balkans meant that Germany was about to lose its main supplies of oil and food. The reserves had been used up, but U.S. troops kept arriving at the rate of 10,000 per day.
Having suffered over 6 million casualties, Germany moved towards peace. Prince Maximilian of Baden took charge of a new government as Chancellor of Germany to negotiate with the Allies. Telegraphic negotiations with President Wilson began immediately, in the vain hope that better terms would be offered than by the British and French. Instead Wilson demanded the abdication of the Kaiser. There was no resistance when the social democrat Philipp Scheidemann on 9 November declared Germany to be a republic. Imperial Germany was dead; a new Germany had been born: the Weimar Republic.