The government introduced a large number of reforms in the following months, introducing various civil liberties and labor rights. The SPD government, committed to parliamentary liberal democracy, utilised military force against more radical communist groups, leading to a permanent split between the SPD and the USPD (later the KPD). The SPD was the largest party during the first 13 years of the new Weimar Republic. It decisively won the 1919 federal election with 37.9% of votes, and Ebert became the first President in February. The position of Chancellor was held by Social Democrats until the 1920 federal election, when the SPD lost a substantial portion of its support, falling to 22% of votes. After this, the SPD yielded the Chancellery to other parties, though it remained in government until 1924. Friedrich Ebert died in 1925 and was succeeded by conservative Paul von Hindenburg. After making gains in the 1928 federal election, the SPD's Hermann Müller became Chancellor. Germany was struck hard by the Great Depression and, unable to negotiate an effective response to the crisis, Müller resigned in 1930. The SPD was politically sidelined as the Nazi Party gained popularity, and the party's paramilitary wing, the "Reichsbanner Schwarz-Rot-Gold", was frequently involved in violent confrontations with the Nazi Sturmabteilung. The Nazis overtook the SPD as the largest party in July 1932, and Adolf Hitler was appointed Chancellor in January 1933. Of the parties present in the Reichstag during the passage of the Enabling Act of 1933, the SPD was the only one to vote against. The party was formally banned in June, and many Social Democrats were subsequently imprisoned and killed by the Nazi government, while others fled the country; in exile, the party used the name Sopade. After the end of World War II, the re-establishment of the SPD was allowed in the Allied administrations in the Western zones in 1945. In the Soviet occupation zone, the SPD was forcibly merged with the KPD in 1946 to form the Socialist Unity Party of Germany (SED). The SED became the ruling party of East Germany until 1989. In West Germany, the SPD became one of two major parties, alongside the Christian Democratic Union (CDU). In the inaugural 1949 federal election it placed second with 29.2% of votes and led the opposition to the CDU government. In its 1959 Godesberg Program, the party dropped its commitment to Marxism and sought to appeal to middle-class voters, becoming a big tent party of the centre-left.