Austria
The Treaty of Saint-Germain of 1919 (for Hungary the Treaty of Trianon of 1920) confirmed and consolidated the new order of Central Europe which to a great extent had been established in November 1918, creating new states and altering others. The German-speaking parts of Austria which had been part of Austria-Hungary were reduced to a rump state named The Republic of German-Austria (German: "Republik Deutschösterreich"). The desire for "Anschluss" (annexation of Austria to Germany) was a popular opinion shared by all social circles in both Austria and Germany. On 12 November, German-Austria was declared a republic, and named Social Democrat Karl Renner as provisional chancellor. On the same day it drafted a provisional constitution that stated that "German-Austria is a democratic republic" (Article 1) and "German-Austria is an integral part of the German reich" (Article 2). The Treaty of Saint Germain and the Treaty of Versailles explicitly forbid union between Austria and Germany. The treaties also forced German-Austria to rename itself as "Republic of Austria" which consequently led to the first Austrian Republic.
Austria under National Socialism
SDAP, GVP, and DNSAP were clearly, although for different reasons, in favour a union of German Austria with the German state, which was also a republic by that time (Weimar Republic). The CS also tended to favour the union, but differed at first on a different subject - they were split on the idea of continuing the monarchy instead of a republic. Whereas only the KPÖ decidedly spoke against the annexation in the course of the 1920s and 1930s, the monarchists originally spoke up against the annexation and later turned to favor it, after the Bavarian Soviet Republic had failed, and Germany had a conservative government. The Treaty of Saint-Germain, signed 10 September 1919 by Karl Renner (SDAP), first chancellor of the republic, clearly forbade any union with Germany, abolished the monarchy, and clearly stated the First Austrian Republic as an independent country.