A recurring interest for Broszat was why and how National Socialism had taken hold in Germany. "Broszat's driving incentive was to help an understanding of how Germany could sink into barbarity," Kershaw wrote. "That he himself had succumbed to the elan of the Nazi Movement was central to his motivation to elucidate for later generations how it could have happened." In his book "Der Nationalsozialismus" (1960), published in English as "German National Socialism 1919–1945" (1966), Broszat examined Nazi ideology, which he regarded as incoherent. For Broszat, the constants were anti-communism, antisemitism and a perceived need for "Lebensraum". In his view, these were a cloak for the essence of National Socialism: an intense desire to realize the "rebirth" of "the German nation", and irrational hatred of those considered "Volksfeinde" (enemies of the German people) and "Volksfremde" (those foreign to the German "race"). Broszat saw the primary supporters of the Nazis as the middle classes, who turned to Nazism to alleviate their anxieties about impoverishment and "proletarianization" in the wake of hyperinflation in the early 1920s and the mass unemployment that began with the Great Depression.