A lawyer, Hugo Haase joined the SPD in 1887 and was part of the party’s Center, grouped around Karl Kautsky. In 1911, he was elected Chairman of the SPD. With Friedrich Ebert serving as the second chairman from 1913, Haase came to be viewed as the leader of the party’s left wing. Yet above all, he was a fervent pacifist; in 1915, he already called for the SPD to take a strong stance against the government’s path towards war. This put him at loggerheads with the rest of the party’s leadership, which split it apart in the end. The USPD was founded in 1917, with Haase becoming its chairman in turn. During the November Revolution, he was under pressure to restore the unity of the workers’ movement. To do so, he joined the Council of People’s Representatives. Yet the USPD’s influence remained marginal; in both governmental affairs and at the councils’ meeting, the SPD set the agenda. After the bloody Skirmish of the Berlin Schloss, Haase and the other USPD People’s Representatives stepped down. At that point, the party faced more and more pressure from both sides - the SPD on the right and the newly founded KPD on the left. It garnered only 7.6% of the votes in the National Assembly elections. Hugo Haase headed its parliamentary group. He was murdered in the fall of 1919.

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Georg Ledebour was one of the strongest opponents of the SPD’s Burgfrieden policy. He publicly called for resistance against the Reich leadership’s war policy. Together with Hugo Haase and other leading left-wing members of the SPD, he initiated the 1917 breakaway of the USPD, which opposed the Kaiserreich’s foreign and war policy from then on. During the November Revolution, he boycotted the party’s cooperation with the SPD in the Council of People’s Representatives. As a USPD leader, he became a Member of the National Assembly in 1919, continuing on after that as a Member of the Reichstag. After a large majority of USPD members joined either the KPD or the SPD, he remained leader of the party up to 1923. Later on, he left the remains of the USPD and represented socialist splinter groups.

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Breitscheid left the SPD to join the newly founded USPD during the war, in 1917. He was the editor of the party’s weekly publication “The Socialist” from 1918 to its closure in 1922. As representative of the USPD, he took on the office of Interior Minister in the first Prussian cabinet of the revolution from 1918 to 1919. In 1922, together with many other USPD members, he joined the SPD. Breitscheid was one of the SPD’s most important foreign policy spokesmen. In this role, he actively supported Stresemann’s Locarno policy. Stresemann appointed him to the League of Nations delegation in 1926. After the Nazis seized power, Breitscheid fled into exile, maintaining contact with the resistance. He was arrested in France in 1940 and died in Buchenwald concentration camp in 1944.

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Luise Zietz came from humble background. She started promoting workers’ concerns in the 1890s. In 1908, she was able to officially join the SPD and with Clara Zetkin, she became one of the first women in the party’s leadership. Within the party, she was much appreciated because of her political talent and rhetorical skills. During the war, she was one of the detractors of the SPD’s Burgfrieden policy and in 1917, helped the USPD split off from the SPD. In 1919, she was elected to the National Assembly. She went on to serve as a member of the Reichstag up to her death in 1922.

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Born in Austria, Hilferding joined the USPD in 1919 and became editor-in-chief of its core publication “Freiheit” (Freedom) in the same year. He pushed strongly for the party to rejoin the SPD. This was realized in 1922. After the merger, Hilferding served as an SPD Member of the Reichstag from 1924. In 1923, he was Finance Minister for a few weeks. Hilferding took this post on again from 1928 to 1929. Due to the stock market crash and a falling out with Reichsbank President Schacht, he resigned. After the Nazis seized power, Hilferding went into exile. He was arrested by the Gestapo in Paris in 1941 and died a few days later in the Gestapo’s prison.

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