Obviously, Alberto Gonzales is not a prisoner of war but a Presidential nominee and is therefore not protected by the Third Geneva Convention or any related legislation. Nor is he protected by the fifth amendment, as he is not going to be placed on trial for a crime.
Our federal anti-torture statute, Title 18, Part I, Chapter 113C of the U.S. Code states (emphasis mine):
Whoever outside the United States commits or attempts to commit torture shall be fined under this title or imprisoned not more than 20 years, or both, and if death results to any person from conduct prohibited by this subsection, shall be punished by death or imprisoned for any term of years or for life.
One might expect that this is followed by a similar statement beginning "Whoever
inside the United States..." It isn't.
Even the Torture Victim Protection Act of 1991 limits liability to (emphasis mine again)
An individual who, under actual or apparent authority, or color of law, of any foreign nation—
“(1) subjects an individual to torture shall, in a civil action, be liable for damages to that individual; or
“(2) subjects an individual to extrajudicial killing shall, in a civil action, be liable for damages to the individual’s legal representative, or to any person who may be a claimant in an action for wrongful death.
The emphasized words clearly imply that a US citizen committing torture for the US government is not liable under the act.
It's not really that torture is supposed to be accepted. Rather, Brendan I. Koerner, Slate's Explainer, writes, "Domestic incidents of torture are covered by state criminal statutes."
In the case of the confirmation hearings, the relevant code is that of Washington, D.C. the D.C. Code has to say about torture. In fact, the code refers to torture 5 times: twice in the context of child abuse, and once in the obscenity code. All but the last are clearly irrelevant. The obscenity law (Division IV, Title 22, Subtitle I, Chapter 22, § 22-2201) states
(b)(1) It shall be unlawful in the District of Columbia for any person knowingly:
(A) To sell, deliver, distribute, or provide, or offer or agree to sell, deliver, distribute, or provide to a minor:
(i) Any picture, photograph, drawing, sculpture, motion picture film, or similar visual representation or image of a person or portion of the human body, which depicts nudity, sexual conduct, or sado-masochistic abuse and which taken as a whole is patently offensive because it affronts prevailing standards in the adult community as a whole with respect to what is suitable material for minors; or
(ii) Any book, magazine, or other printed matter however reproduced or sound recording, which depicts nudity, sexual conduct, or sado-masochistic abuse or which contains explicit and detailed verbal descriptions or narrative accounts of sexual excitement, sexual conduct, or sado-masochistic abuse and which taken as a whole is patently offensive because it affronts prevailing standards in the adult community as a whole with respect to what is suitable material for minors; or
(B) To exhibit to a minor, or to sell or provide to a minor an admission ticket to, or pass to, or to admit a minor to, premises whereon there is exhibited, a motion picture, show, or other presentation which, in whole or in part, depicts nudity, sexual conduct, or sado-masochistic abuse and which taken as a whole is patently offensive because it affronts prevailing standards in the adult community as a whole with respect to what is suitable material for minors.
...
(2) For purposes of paragraph (1) of this subsection:
(E) The term "sado-masochistic abuse" includes flagellation or torture by or upon a person clad in undergarments or a mask or bizarre costume, or the condition of being fettered, bound, or otherwise physically restrained on the part of one so clothed.
Thus, the act would not be illegal in itself, though C-SPAN might have to censor its coverage of the hearings, especially if the involved parties are scantily clad.
Having established the legality of torture, we next establish the necessity, a much simpler task. Gonzales is on the verge of becoming the nation's most powerful law enforcement officer yet his record of legally questionable activity suggests that he may be unable to perform this task competently. We must know all there is to know about the decisions he has made, and, as Trent Lott might say, we're not going to find that information by withholding pancakes.