Here is what the Geneva Convention says:
Art. 75. Fundamental guarantees
1. In so far as they are affected by a situation referred to in Article 1 of this Protocol, persons who are in the power of a Party to the conflict and who do not benefit from more favourable treatment under the Conventions or under this Protocol shall be treated humanely in all circumstances and shall enjoy, as a minimum, the protection provided by this Article without any adverse distinction based upon race, colour, sex, language, religion or belief, political or other opinion, national or social origin, wealth, birth or other status, or on any other similar criteria. Each Party shall respect the person, honour, convictions and religious practices of all such persons.
2. The following acts are and shall remain prohibited at any time and in any place whatsoever, whether committed by civilian or by military agents: (a) violence to the life, health, or physical or mental well-being of persons, in particular: (i) murder; (ii) torture of all kinds, whether physical or mental; (iii) corporal punishment; and (iv) mutilation;
(b) outrages upon personal dignity, in particular humiliating and degrading treatment, enforced prostitution and any form of indecent assault; (c) the taking of hostages; (d) collective punishments; and (e) threats to commit any of the foregoing acts.
http://www.globalissuesgroup.com/geneva/protocol1.html#75
Art. 86. Failure to act
1. The High Contracting Parties and the Parties to the conflict shall repress grave breaches, and take measures necessary to suppress all other breaches, of the Conventions or of this Protocol which result from a failure to act when under a duty to do so.
2. The fact that a breach of the Conventions or of this Protocol was committed by a subordinate does not absolve his superiors from penal disciplinary responsibility, as the case may be, if they knew, or had information which should have enabled them to conclude in the circumstances at the time, that he was committing or was going to commit such a breach and if they did not take all feasible measures within their power to prevent or repress the breach.
http://www.globalissuesgroup.com/geneva/protocol1.html#86
Art. 87. Duty of commanders
1. The High Contracting Parties and the Parties to the conflict shall require military commanders, with respect to members of the armed forces under their command and other persons under their control, to prevent and, where necessary, to suppress and to report to competent authorities breaches of the Conventions and of this Protocol.
2. In order to prevent and suppress breaches, High Contracting Parties and Parties to the conflict shall require that, commensurate with their level of responsibility, commanders ensure that members of the armed forces under their command are aware of their obligations under the Conventions and this Protocol.
3. The High Contracting Parties and Parties to the conflict shall require any commander who is aware that subordinates or other persons under his control are going to commit or have committed a breach of the Conventions or of this Protocol, to initiate such steps as are necessary to prevent such violations of the Conventions or this Protocol, and, where appropriate, to initiate disciplinary or penal action against violators thereof.
http://www.globalissuesgroup.com/geneva/protocol1.html#87
Read the bold sentences carefully and you will see:
1) Mental torture, and indecent assault are a grave breach of the Geneva Convention, whether carried out by civillians or soldiers
2) Soldiers and their superiors have a responsibility to report such breaches
3) The authorities have a responsibility to prosecute ALL those responsible for such breaches, civillian or solder, active participant or person who knew a breach was occuring but did not take action.
This means that by NOT arresting the civillian interrogators, the US millitary is commiting yet another war crime, as is every person in a position of responsibility who does NOT force such prosecutions - including Bush himself.
Bush doesn't have to order such acts to be a war criminal, he merely has to condone them by refusing to prosecute those who commit them.