Who were the Nazi's supporters?

In the book The Nazi Seizure of Power, Allen presents Northeim, a small town in North-central Germany, as a relatively stable and diverse town, but not without it's class conflicts. He notes early on that even when the Great Depression hit the town, affectingly almost exclusively unskilled workers, they remained steadfastly in the hands of the socialists. In fact, the Nazis base of power was the bourgeoisie, the middle and upper-middle class, who had lost, relative to the underclass, very little during the depression.

The SDP had a large presence in Northheim, an extremely class-conscious town. The party kept it's traditional organization and represented those who were seen as the lower classes, as it had always done since the beginning of the Weimar Republic. Yet when the depression hit, "the workers remained steadfastly in favor of the status quo while the middle class, only marginally hurt by the economic constriction, turned to revolution" (24).

Allen offers an explanation for why the middle class was drawn to the Nazi party: Many former military and nationalist groups, or antisemites, joined because of the far-right rhetoric of the party. Students joined because "its vague ideology of a new society in which patriotic solidarity would supplant Germany's rigid class distinctions" (25). But why didn't the underclasses turn to Nazism to the same degree? Surely the idea of a classless society unified by national identity held some appeal to them more than those with the comforts of the class structure?

The Nazi's local branches were highly versatile, able to manipulate their vague ideology to appeal to almost all classes of society, from businessmen to peasants. But I would venture to guess that what kept the poor away from the Nazis, at least initially, was the entrenched nature of the SPD. Allen says early in the book that the SPD organization held together the lower classes of Northeim, and forged a very important part of the community right up until the depression. It was tightly knit and active in the community, offering, as I see it, the only real competitor to the local Nazi branch. There had even been violent clashes between the parties.

But luckily for the Nazis, those who were not committed to the SDP and democracy were abundant, and their local system of of self-financing and speaker who could, with constant feedback, tailor their speeches to their audience. The middle and upper classes were also more likely to be educated and older, being both aware of national political sentiment and Germany's proud imperial past, and these factors coupled with the perceived failure of Democracy leading up to the depression, with the unemployment benefits issue and constant turnover of government, to the poor economic policies during the depression itself, likely radicalized what was left of the middle and upper classes as the depression spread to them too.