Date of Birth: 09/29/1863
The son of a shoemaker and a small Jewish merchant. After graduating from high school he studied at the University Albertina in Konigsberg, where he studied law and socially and science. After graduation worked as a lawyer, he has been involved in many political processes, gradually linking their lives with social-democratic movement in Germany. In 1912 he moved to Berlin.
In the years 1911-1917 Haase - one of the chairmen of the Social Democratic Party. The deputy of the Reichstag in 1897-1907 years and 1912-1918 years. August 4, 1914 gave a speech in the Reichstag to justify the vote of the Social-Democratic Party for war credits. Later takes rezkoantivoennuyu position and broke off relations with the Social Democrats. In April 1917, it creates together with Karl Kautsky and other like-minded Independent Social Democratic Party in Germany. During the November Revolution of 1918, together with Ebert, chairman of the Provisional Government of Germany - narodnyhupolnomochennyh Council.
After the founding of the Communist Party of Germany opposed the radical wing of his party, insisted on co-operation with the Communists. At the same time he condemned the violence by government forces over the rebels seamen during the Christmas of 1918, organized by Ebert`s orders.