After 1918, Claß met Adolf Hitler and supported his putsch in 1923. In 1931, he was one of the founding members of the Harzburg Front. From 1933 to 1939, Claß was a member of the National Socialist Party in the Reichstag. It is noteworthy that his radical imperialism, pan-Germanism and anti-Semitism had a significant influence on the Nazis.