SPD and the World War
In the decade after 1900, the Social Democratic Party of Germany (SPD) was the leading force in Germany's labour movement. With 35% of the national votes and 110 seats in the Reichstag elected in 1912, the Social Democrats had grown into the largest political party in Germany. Party membership was around one million, and the party newspaper (Vorwärts) attracted 1.5 million subscribers. The trade unions had 2.5 million members, most of whom probably supported the Social Democrats. In addition, there were numerous co-operative societies (for example, apartment co-ops, shop co-ops, etc.), and other organizations directly linked to the SPD and the labor unions, or else adhering to Social Democratic ideology. Other notable parties in the Reichstag of 1912 were the Catholic Centre Party (91 seats), the German Conservative Party (43), the National Liberal Party (45), the Progressive People's Party (42), the Polish Party (18), the German Reich Party (14), the Economic Union (10), and the Alsace-Lorraine Party (9).
At the congresses of the Second Socialist International, the SPD had always agreed to resolutions asking for combined action of Socialists in case of a war. Following the assassination of Archduke Franz Ferdinand in Sarajevo, the SPD, like other socialist parties in Europe, organised anti-war demonstrations during the July Crisis. After Rosa Luxemburg called for disobedience and rejection of war in the name of the entire party as a representative of the left wing of the party, the Imperial government planned to arrest the party leaders immediately at the onset of war. Friedrich Ebert, one of the two party leaders since 1913, travelled to Zürich with Otto Braun to save the party's funds from being confiscated.
After Germany declared war on the Russian Empire on 1 August 1914, the majority of the SPD newspapers shared the general enthusiasm for the war (the "Spirit of 1914"), particularly because they viewed the Russian Empire as the most reactionary and anti-socialist power in Europe. In the first days of August, the editors believed themselves to be in line with the late August Bebel, who had died the previous year. In 1904, he declared in the Reichstag that the SPD would support an armed defence of Germany against a foreign attack. In 1907, at a party convention in Essen, he even promised that he himself would "shoulder the gun" if it was to fight against Russia, the "enemy of all culture and all the suppressed". In the face of the general enthusiasm for the war among the population, which foresaw an attack by the Entente powers, many SPD deputies worried they might lose many of their voters with their consistent pacifism. In addition, the government of Imperial Chancellor Theobald von Bethmann-Hollweg threatened to outlaw all parties in case of war. On the other hand, the chancellor exploited the anti-Russian stance of the SPD to procure the party's approval for the war.
The party leadership and the party's deputies were split on the issue of support for the war: 96 deputies, including Friedrich Ebert, approved the war bonds demanded by the Imperial government. There were 14 deputies, headed by the second party leader, Hugo Haase, who spoke out against the bonds, but nevertheless followed party voting instructions and raised their hands in favour.
Thus, the entire SPD faction in the Reichstag voted in favour of the war bonds on 4 August 1914. It was with those decisions by the party and the unions that the full mobilisation of the German Army became possible. Haase explained the decision against his will with the words: "We will not let the fatherland alone in the hour of need!" The Emperor welcomed the so-called "truce" (Burgfrieden), declaring: "Ich kenne keine Parteien mehr, ich kenne nur noch Deutsche!" ("I no longer see parties, I see only Germans!").
Even Karl Liebknecht, who became one of the most outspoken opponents of the war, initially followed the line of the party that his father, Wilhelm Liebknecht, had cofounded: he abstained from voting and did not defy his own political colleagues. However, a few days later he joined the Gruppe Internationale (Group International) that Rosa Luxemburg had founded on 5 August 1914 with Franz Mehring, Wilhelm Pieck, and four others from the left wing of the party, which adhered to the prewar resolutions of the SPD. From that group emerged the Spartacus League (Spartakusbund) on 1 January 1916.
On 2 December 1914, Liebknecht voted against further war bonds, the only deputy of any party in the Reichstag to do so. Although he was not permitted to speak in the Reichstag to explain his vote, what he had planned to say was made public through the circulation of a leaflet that was claimed to be unlawful:
The present war was not willed by any of the nations participating in it and it is not waged in the interest of the Germans or any other people. It is an imperialist war, a war for capitalist control of the world market, for the political domination of huge territories and to give scope to industrial and banking capital.
Because of high demand, this leaflet was soon printed and evolved into the so-called "Political Letters" (German: Politische Briefe), collections of which were later published in defiance of the censorship laws under the name "Spartacus Letters" (Spartakusbriefe). As of December 1916, these were replaced by the journal Spartakus, which appeared irregularly until November 1918.
This open opposition against the party line put Liebknecht at odds with some party members around Haase who were against the war bonds themselves. In February 1915, at the instigation of the SPD party leadership, Liebknecht was conscripted for military service to dispose of him, the only SPD deputy to be so treated. Because of his attempts to organise objectors against the war, he was expelled from the SPD, and in June 1916, he was sentenced on a charge of high treason to four years in prison. While Liebknecht was in the army, Rosa Luxemburg wrote most of the "Spartacus Letters". After serving a prison sentence, she was put back in jail under "preventive detention" until the war ended.
The SPD Split
As the war dragged on and the death tolls rose, more SPD members began to question the adherence to the Burgfrieden (the truce in domestic politics) of 1914. The SPD also objected to the domestic misery that followed the dismissal of Erich von Falkenhayn as Chief of the General Staff in 1916. His replacement, Paul von Hindenburg, introduced the Hindenburg Programme by which the guidelines of German policy were de facto set by the Supreme Army Command (German: Oberste Heeresleitung), not the emperor and the chancellor. Hindenburg's subordinate, Erich Ludendorff, took on broad responsibilities for directing wartime policies that were extensive. Although the Emperor and Hindenburg were his nominal superiors, it was Ludendorff who made the important decisions. Hindenburg and Ludendorff persisted with ruthless strategies aimed at achieving military victory, pursued expansionist and aggressive war goals and subjugated civilian life to the needs of the war and the war economy. For the labour force, that often meant 12-hour work days at minimal wages with inadequate food. The Hilfsdienstgesetz (Auxiliary Service Law) forced all men not in the armed forces to work.
After the outbreak of the Russian February Revolution in 1917, the first organised strikes erupted in German armament factories in March and April, with about 300,000 workers going on strike. The strike was organized by a group called the Revolutionary Stewards (Revolutionäre Obleute), led by their spokesman Richard Müller. The group emerged from a network of left-wing unionists who disagreed with the support of the war that came from the union leadership. The American entry into World War I on 6 April 1917 threatened further deterioration in Germany's military position. Hindenburg and Ludendorff had called for an end to the moratorium on attacks on neutral shipping in the Atlantic, which had been imposed when the Lusitania, a British ship carrying US citizens, was sunk off Ireland in 1915. Their decision signaled a new strategy to stop the flow of US materiel to France to make a German victory (or at least a peace settlement on German terms) possible before the United States entered the war as a combatant. The emperor tried to appease the population in his Easter address of 7 April by promising democratic elections in Prussia after the war, but lack of progress in bringing the war to a satisfactory end dulled its effect. Opposition to the war among munitions workers continued to rise, and what had been a united front in favour of the war split into two sharply divided groups.
After the SPD leadership, under Friedrich Ebert, excluded the opponents of the war from his party, the Spartacists joined with so-called "Revisionists" such as Eduard Bernstein and Centrists such as Karl Kautsky to found the fully anti-war Independent Social Democratic Party of Germany (USPD) under the leadership of Hugo Haase on 9 April 1917. The SPD was now known as the Majority Social Democratic Party of Germany (MSPD) and continued to be led by Friedrich Ebert. The USPD demanded an immediate end to the war and a further democratisation of Germany but did not have a unified agenda for social policies. The Spartacist League, which until then had opposed a split of the party, now made up the left wing of the USPD. Both the USPD and the Spartacists continued their anti-war propaganda in factories, especially in the armament plants.