You'll remember, of course (if not from personal experience) that the Nazi defendants at Nuremberg and later war-crime trials claimed they were merely following orders. In all the many thousands of such trials this line of defense was never accepted, but it did catch broad public attention.
Eichmann tried it, too, at his trial in Jerusalem. Quite strenuously, as a matter of fact.
A number of years prior to his trial (which took place in 1961) the Israeli courts had dealt with the matter with Israeli war criminals, most importantly the ones from the Kfar Kassem murders. The Supreme Court made the distinction between illegal orders and categorically illegal orders, the first being ones that soldiers must follow, the second being one that soldiers are forbidden to follow, and will be court-martialed if they do; the court also gave the helpful definition that what marks the categorically illegal orders is that a black flag flies above them. (I wrote more about this in Right to Exist).
Of course, as you'd expect, none of this happened in a vacuum, and actually the discussion began some 2,000 years earlier.
We're in Kiddushin these days, I remind you. The Gemara discusses various aspects of messengers fulfilling precepts. This started with the question if a man is allowed to betroth a woman via a messenger, who will bring her the contract or money required for the betrothal. Quite rapidly, however, the discussion broadens out to include the question if a man can tell someone else to transgress, and if so, who bears responsibility. The answer given on page 42 of Kiddushin is that this can't happen: ein shaliach le'dvar aveira: a man cannot be a courier for a transgression, but bears responsibility for whatever he does.
On the next page, 43a, the discussion becomes even more explicit, when a Braita (a Mishniac text, i.e. before the 3rd century) states that if a man sends another to kill someone, the responsibility is on the killer alone, not the initiator. Shamai the Elder, however (about 2,100 years ago) disagrees,and brings the story of the prophet Nathan who admonishes King David for having engineered the death in battle of Uriya, so as to marry her widow, Batsheva: Nathan sees this as murder, in spite of the fact that there were actually two other agents between King David and Uriya's death, Yoav the general, and the Amonites who actually did the killing, on the field of battle.
The Gemara then goes into a discussion about whether murder is the same as lesser transgressions, in a fascinating precedent for the 20th century distinction between illegal and categorically illegal. Except, of course, that the Sages see it from the opposite direction: the killers are clearly criminally responsible, the question is to what extent criminal responsibility can be ascribed to the initiators.
(By the way, if you've never read that book, Right to Exist, you ought to. Since I had to work with an editor, and it was published through a real publishing house, it's much more serious than a blog. Many people, including the reviewer of the New York Times, felt it to be a good book.
(Und wenn Sie es auf Deutsch lesen wollen, das geht auch.)
As I always mention, this thread began here.