Following the annexation of Austria in March 1938, it seemed that Zweigelt's dream was about to become true. He would be able to lead "his" Klosterneuburg to new heights as a sister institute to the much larger State School of Viticulture, Fruit Growing and Horticulture in Geisenheim am Rhein. In his capacity as Head and subsequently (after 1943) Director of Klosterneuburg, Zweigelt did everything he possibly could to turn the institute into a "stronghold of National Socialism". However, he began to be caught between the different fronts. Adherents of the Austro-Fascist Dollfuß-Schuschnigg regime were keen to prevent his rise, and they were not alone in this aspiration. Zweigelt also found himself in the way of other rival colleagues who had only recently embraced the ideas of National Socialism. However, during the summer of 1938, he succeeded in forcing numerous undesirable teaching staff members to leave the school. These were then replaced by dyed-in-the-wool National Socialists. The Nazi Government in Germany adopted the most progressive viticulture policies in the world and soon gained international recognition. The culmination and end of this development occurred at an international viticulture congress staged in Bad Kreuznach in late August 1939. Zweigelt, now elevated to the status of Reich Official, was one of the participants.