George J Annas
The Nazi doctors defended themselves primarily by arguing that they were engaged in necessary wartime medical research and were following the orders of their superiors. These defenses were rejected because they are at odds with the Nuremberg Principles, articulated a year earlier, at the conclusion of the multinational war crimes trial in 1946, that there are crimes against humanity (such as torture), that individuals can be held to be criminally responsible for committing them, and that obeying orders is no defense.
Annas GJ. Unspeakably Cruel-Torture, Medical Ethics, and the Law. N. Engl. J. Med.. 2005;352(20):2127-2132.