Ehlers' time at college was surely influenced by the revolutions, inflation, unemployment, and political radicalization that characterized Germany following World War I, and Ehler became exceedingly active in student political groups such as the "Verband der Vereine Deutscher Studenten" (United German Student Union).

Ehlers began studying at the University of Bonn in the summer of 1924, where he began attending the lectures of the famous but controversial