"I was only following orders."
The so-called "Nuremberg defense" was used by Nazi war criminals at the Nuremberg War Trials following World War II to argue that they should not be held responsible for their crimes because they were carrying out the orders of their superiors according to the existing laws of their nation. The Nuremberg defense was rejected outright by the Tribunal judges, who ruled that the language of the Nuremberg Principles laid out in the UN General Assembly Resolution of December 11, 1946 still demanded individual responsibility despite what the laws of a given nation may state.
In the years since, the term "Nuremberg defense" has entered common parlance and is applied whenever anyone tries to get away with something by stating, "I was just doing my job."