Based on the concept of “militant democracy” developed by the jurist Karl Loewenstein, this study explores how the First Czechoslovak Republic was able to defend itself against changing domestic and foreign threats in the years 1918–1938. The approach is, on the one hand, a genuinely political and historical one, because it is a question of which institutions the ČSR created for the purpose of self-assertion. Here, the focus is primarily on the intelligence services and its work in the initially “völkisch” and later National Socialist sphere. After 1933, Czechoslovakia became a place of refuge for emigrants from Nazi Germany. The roles played by German and German-Jewish emigrants in the intelligence service and for propaganda purposes of the state should thus be examined as well. A modern “intellectual history” will also link with recent findings of exile research accentuated by cultural history, investigating the question of how emigrants influenced the political culture in their host country, in particular the public, political and academic debate on the future of democracy.