Political extremism is often explained through ideology or economic crisis. This new research shows that social dynamics inside local communities may also play a central role in how totalitarian movements grow.
The discussion paper Hysteresis and Selection in the Rise of Fascism: The ‘Ordinary Men’ of the Nazi Party by Luis Bosshart, Max Deter, Leander Heldring, Cathrin Mohr, and Matthias Weigand examines who joined the Nazi Party and how it became a mass movement. The paper asks a longstanding question: were Nazi Party members mainly ideological extremists, or were many simply ordinary citizens who became part of the movement over time?
This question matters because it speaks to a broader concern that goes beyond German history. If totalitarian movements depend mostly on a small group of extremists, they may remain limited. But if they can attract ordinary people through social influence, they may spread much more widely.
To answer this question, the researchers built a unique historical dataset. They digitized the near-complete surviving membership records of the Nazi Party, officially the National Socialist German Workers’ Party, covering around 11 million people, and linked these records to German population and industrial census data from the interwar period.
Earlier research relied on much smaller samples or county-level averages. The new dataset makes it possible to study individual members directly and to trace when and where people joined, down to municipalities, occupations, and family groups.
One central finding is that the composition of the party changed over time. Early members were not fully representative of German society. They were more likely to be male and somewhat more likely to come from middle-class occupations such as small business owners, independent professionals, and civil servants.
As the party expanded, this changed. New members increasingly resembled the general population. By the late 1930s, the social differences between party members and non-members had narrowed considerably. The authors interpret this as evidence that the party moved from a selective political group to a broad mass organization.
The study also shows that people did not join at random. Membership often spread in discontinuous waves. Once a few people in a town joined, others in the same community were much more likely to follow. The same pattern appears inside workplaces and even among people sharing the same surname within a municipality, which likely captures family networks.
The authors describe this as “hysteresis,” meaning that early events continue to shape later outcomes. In simple terms, once the party gained a foothold in a local group, that early presence made future joining more likely. The decision to join was therefore shaped not only by personal beliefs but also by who was already inside a person’s social circle.
This finding shifts attention from individual ideology to coordination. Coordination means people adjusting their decisions based on what others around them are doing. The paper suggests that local peer effects – influence from colleagues, neighbors, and relatives – helped transform the party from a fringe movement into a national force.
The study also compares regular party members with the SS, the paramilitary organization that became central to Nazi repression. Here the pattern is different. SS members remained much more selective: they were younger, better educated, and more often employed in professional or administrative occupations.
This distinction is important. It suggests that the totalitarian Nazi regime in Germany relied on two different mechanisms: The broader party mobilized millions of “ordinary” citizens, while the SS recruited a narrower group that was more ideologically committed.
The paper also links local party strength to later persecution in the Holocaust. Municipalities with higher party membership later saw higher levels of deportation and emigration of Jews. The authors are careful not to claim direct causation, but the association suggests that stronger local party networks mattered for how Nazi policies were implemented on the ground.
The broader lesson is that extremist movements may not require a population dominated by committed radicals. They can grow when social pressure, local networks, and political uncertainty make participation seem “normal”.
This makes the study relevant today. It shows how democratic societies can become vulnerable when ordinary social relationships become channels for political radicalization. Understanding those local dynamics is essential for understanding how totalitarian movements rise.
About the Authors
Luis Bosshart
Academy Scholar at the Harvard Academy for International and Area Studies at the Weatherhead Center. His work focuses on political economy, development, and economic history.
Max Deter
Postdoctoral Researcher at the University of Potsdam and part of the Berlin School of Economics. His research focuses on political economy, regional economics, economic history, and labor economics.
Leander Heldring
Associate Professor, Kellogg School of Management, Northwestern University. His research studies political economy, economic history, and economic development.
Cathrin Mohr
Professor at the Kiel Institute for the World Economy and the University of Hamburg. Her work focuses on political economy and economic history.
Matthias Weigand
PhD student in Economics at Harvard University. His work examines questions in political economy and industrial organization through the lens of economic history.
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The Harvard Gazette: Who joined the Nazi Party
