Can large-scale interventions shift political norms? In a major denazification program, millions of Germans were questioned about their political past by courts. I document how denazification shaped the emerging political landscape in postwar Germany. Using three identification strategies, I find that broader denazification reduced the demand for nationalist policies and changed social norms. Differences seem driven by mass rather than elite cases and political consequences are observed absent major differences in punishment. The results indicate that the breadth of transitional justice may be more important than its severity. More broadly, the findings illustrate how deliberate public interventions may shift social norms and political demand at scale.