to report back, the SPD had already decided to support the first war loans in the Reichstag. During World War I, Müller supported the Burgfrieden. He was used by the SPD leadership to deal with arguments with the party's left wing and as an in-house censor for the party newspaper Vorwärts to avoid an outright ban by the military authorities. Müller was close to the group around Eduard David and supported both the Treaty of Brest-Litovsk with Russia and the entry of the SPD into the government of Max von Baden in October 1918. First elected in a by-election in 1916, Müller was a member of the Reichstag until 1918. 1918 to 1920 In the German Revolution of 1918-19, Müller was a member of the Greater Berlin executive council (Vollzugsrat der Arbeiter- und Soldatenräte) where he represented the position of the SPD leadership, arguing in favor of elections to the Weimar National Assembly. He later published a book on his experience during the revolution. In January 1919, Müller was elected to the National Assembly. In February 1919, Ebert became President of Germany and appointed Philipp Scheidemann as Ministerpräsident (head of government). These two had been the joint chairmen of the SPD and now replacements had to be found. Müller and Otto Wels were elected with 373 and 291 out of 376 votes, respectively. Wels focused on internal leadership and organization, whilst Müller was the external representative of the party. In 1919 and 1920–28, Müller was also leader of the parliamentary fraction (Fraktionsvorsitzender ) in the National Assembly and then the Reichstag. He was nominated as the chairman of the Reichstag's Committee on Foreign Affairs. After 1920, he was a candidate for the Reichstag for Franconia and changed his name to Müller-Franken, to distinguish himself from other members named Müller. After Scheidemann resigned in June 1919, Müller was asked to succeed him as head of government but declined. Under the new Ministerpräsident and later Chancellor Gustav Bauer, Müller became Reichsaußenminister (Foreign Minister) on 21 June 1919. In this capacity, he went to Versailles and with Colonial Minister Johannes Bell signed the Treaty of Versailles for Germany on 29 June 1919. After the resignation of the Bauer cabinet, which followe the Kapp-Lüttwitz Putsch in March 1920, Müller accepted Ebert's offer of becoming Chancellor and formed a new government. Under his leadership, the government suppressed the left-wing uprisings like that in the Ruhr