If a case is to be made that there should be special exceptions in the law to the worst terrorists with knowledge that will certainly prevent imminent mass destruction, then it must be air-tight: only those cases matching very stringent criteria of imminent threat, and sanctioned by the President, a special court, and a special committee of Congress should be authorized; to be carried out only by a very select group of interrogators; with a full accounting of the valid information gained from said torture, and with records recorded for public release in the future.

If torture is to happen, it should not be sanctioned by a court, a president, a committee of congress, and so on, because these would validate the method in the public sphere and in doing so would carve-out a culture in which torture may be tolerated. Mark Bowden's argument is a little problematic, but it's interesting, which is that if torture is to happen, it must be done by agents who know they are putting their lives on the line, and if the crime pays off, the legal system will have the good sense not to give them hell, and if the crime is brazen and ghastly, then they will be imprisoned for it. Bowden is essentially arguing for surrendering the issues to public opinion, who can put it into context. One could argue that this would set a dangerous precedent. But at least it does not create that dishonorable regime in which torture is de jure legalized by the authorities.

That is a fascinating position. On the one hand, torture requires that the law become subordinate to public opinion and disposed of when the public deems it worthwhile; on the other, it requires that barbarity be legal and so undermine the law's respect for humanity.
But what role does public opinion play in the legal system? I can think of two: political interference (by the Justice Dept) in criminal proceedings, or juries acquitting because they accept the crimes as necessary. Can we condone the former without undermining public trust in the government's respect for law? Can we have a policy that approves of prosecutors refusing to pursue a case because the public approves of the crime? On the other hand, how can interrogators operate legally knowing their fate will be up to the whim of a jury? A torture case can come to trial years after the public sense of panic and danger has passed; we forget in retrospect how absolutely evil we considered these people to be; a liberal jury is appointed and the torturers are convicted.
Your point reinforces the conclusion that torture should be illegal, period. Never authorized, never carried out, always prosecuted. I have no problem with that position. If a Jack Bauer thinks he will save the world by torturing someone, then he can try to convince a jury to acquit him, or martyr his liberty for his country. This is a minefield no matter which was one approaches it, best avoided completely.