I think you're on to something when you write "The interrogator must be willing to take responsibility and accept punishment for any illegal methods."

One of the big concerns I have about the torture issue is the consequences of legitimizing and normalizing extreme interrogation methods. Torture should not become routine, lest its use expand into areas where there's a less compelling case for urgency. "Mission creep" is a fact of life, and laws establish boundaries to contain it.

When extreme interrogation methods are illegal and understood to be unacceptable, it sharpens the decision for anyone who believes that a situation is serious enough to justify torture. It's good for interrogators to have to ask themselves "Is it worth losing my job and perhaps facing prosecution?" If the answer is yes, perhaps the extreme methods really are justified.

The American military tradition supports this. Soldiers are counseled that if their consciences are sufficiently bothered by their orders, they must be willing to face a court martial to make their case. Disobedience will be punished, and in extreme cases, disobedience may be justified...and a military court will ultimately make that judgment.

The old saying "it's easier to ask forgiveness than permission" sort of applies here, as long as there's something to forgive. Making torture easy and consequence-free destroys the accountability implied by the need to ask forgiveness. Torture should remain illegal, and those who think it's justified in particular cases can argue for forgiveness on a case-by-case basis. That's how a system of checks-and-balances is supposed to work.