The existence of such crimes and offences and the concept of personal criminal responsibility are recognized and affirmed by paragraph 498 of the U.S. Field Manual on the Laws of Land Warfare. The Navy and Airforce have similar provisions. These manuals do also assert the non-unlawfulness of using nuclear weapons which is somewhat of a paradox.
The manuals expressly provide that "conspiracy, direct incitement, and attempts to commit, as well as complicity in the commission of crimes against peace, crimes against humanity and war crimes are punishable".
The Tribunal notes a remarkable inconsistency here between training and instructions. Officers are told that they cannot rely on the defence of "superior orders" and further that under U.S. military code, one is under an obligation to refuse to obey unlawful orders.
The manuals also blithely ignore the de Martens Clause which obliges a state to justify the use of a new weapon under the existing norms of the Laws of War. The manuals and the de Martens Clause are therefore irreconcilable.
Examples were presented to the Tribunal in which U.S. military personnel either refused to obey orders or asked to be relieved of their command as they did not feel they could carry out their orders.
In a pastoral letter of 1982, American Roman Catholic Bishops stated: "It is never permitted to direct nuclear or conventional weapons to the indiscriminate destruction of whole cities or vast areas of the population".
This does call into question whether or not orders would be followed; some apparently would not be. The military in the U.S. is composed of 30% Catholics. Does this bring into question the reliability of Catholics---should they be relieved from positions of command? Others, who are not religious, may also refuse to obey orders as they hold international law in high esteem.
Professor Boyle has spent a good deal of time with the military and believes that they are strong supporters of the laws of war. This is mainly because the laws of war were originally designed to protect them.
There is also a large amount of pride and self-esteem among the military that they are doing a worthwhile job defending their country; "a good job done professionally". To bomb cities indiscriminately would lead them to be regarded as butchers by civilians, on the scale of a Hitler or Stalin, not the "honourable profession of a soldier". This has greater importance than might otherwise be perceived in the light of the Vietnam experience when some military personnel became ashamed to wear uniforms.
Professor Boyle offered the evidence that although the US Army Field Manual has been used many times to justify the proposition that the use of nuclear weapons can be legal, in fact in terms it never states as such. He quoted the US 1956 Army Field Manual: "The use of explosive 'atomic weapons', whether by air, sea, or land forces, cannot as such [emphasis added by editor] be regarded as violative of international law in the absence of any customary rule of international law or international convention restricting their employment". He went on to point out that a close reading of this paragraph merely indicates that the use of nuclear weapons cannot be regarded as violative of international law solely because they are atomic as opposed to conventional weapons. In other words, there is no one conventional or customary rule of international law that specifically prohibits the use of atomic weapons by that name. The quoted paragraph never states that the actual use of nuclear weapons would not be in violation of the international laws of humanitarian armed conflict and the laws of war. He also pointed out that even the similar statement in the US 1955 Navy Manual which made a grievous error by proclaiming: "In the absence of express prohibition, the use of such weapons against enemy combatants and other military objectives is permitted", never went so far as to assert that nuclear weapons could be used lawfully against civilian population centres, as opposed to legitimate military targets. There is therefore the very interesting likelihood that most contemplated uses of nuclear weapons by US forces are illegal under their own field manuals, despite the cynical interpretation by some commentators.