Why did so many German doctors join the Nazi Party early?

During the Weimar Republic in the mid-twentieth century, more than half of all German physicians became early joiners of the Nazi Party, surpassing the party enrollments of all other professions. From early on, the German Medical Society played the most instrumental role in the Nazi medical program, beginning with the marginalization of Jewish physicians, proceeding to coerced "experimentation," "euthanization," and sterilization, and culminating in genocide via the medicalization of mass murder of Jews and others caricatured and demonized by Nazi ideology. Given the medical oath to "do no harm," many postwar ethical analyses have strained to make sense of these seemingly paradoxical atrocities. Why did physicians act in such a manner? Yet few have tried to explain the self-selected Nazi enrollment of such an overwhelming proportion of the German Medical Society in the first place. This article lends insight into this paradox by exploring some major vulnerabilities, motives, and rationalizations that may have predisposed German physicians to Nazi membership-professional vulnerabilities among physicians in general (valuing conformity and obedience to authority, valuing the prevention of contamination and fighting against mortality, and possessing a basic interest in biomedical knowledge and research), economic factors and motives (related to physician economic insecurity and incentives for economic advancement), and Nazi ideological and historical rationalizations (beliefs about Social Darwinism, eugenics, and the social organism as sacred). Of particular significance for future research and education is the manner in which the persecution of Jewish physician colleagues was rationalized in the name of medical ethics itself. Giving proper consideration to the forces that fueled "Nazi Medicine" is of great importance, as it can highlight the conditions and motivations that make physicians susceptible to misapplications of medicine, and guide us toward prevention of future abuse.