Why were the german social democrats unable to form a government of their own in 1919?

Answer 1

The social democrats were not able to form a government of their own in 1919 because they did not have the majority of the support of the people, who were still reeling after the capitulation of the First world war in november 1918.

The Social democrats were forced into a coalition - the Weimar Coalition, with the German Democratic Party (DDP), and the Catholic Centre Party. These 3 parties were mostly committed to the new Weimar Republic.

The social democrats also lost further support after signing the Treaty of Versailes, in which Germany had to accept responsibility for starting the first world war. Which of course many Germans disagreed with. Of all the political parties, it was the Social Democrats who were most associated with the 'stab in the back' - that the German army had been stabbed in the back by the left wing politicians.

Throughout the 1920's, the Social democrats were forced to include more right wing parties in their coalition to hold government, as German resentment at the Treaty of Versailles and the payment of reparations. The social democrats began to get stronger until the 1929 Great Depression hit Germany.

Answer 2

Because they didn't get sufficient votes to have an overall majority over all other parties.