"Your honor, the prosecution would like to request a change of venue."
"Oh? To where?"
"Look, if you don't want to do it here, we can always have the trial in Lubbock, Texas."
Pause. "Your honor, the prosecution would like to drop the indictment."
There's not too many places in this country where twelve random people are guaranteed to all take the Daily Kos line on interrogation. Of course, there could be a conviction in Lubbock. Jury selection is an art and their decisions can be hard to predict. But I bet AG Holder doesn't have anyone knocking on his door wanting to be lead prosecutor.
I've addressed the issues with torture before. It's ugly, it stains our souls, but it works and sometimes it's preferable to the alternatives when dealing with terrorists. The alternative isn't just accepting a higher risk of terrorist attacks on the USA. It's also dropping bombs on a family of Afghan Hatfields because the local McCoys provided a "reliable report" that they were sheltering a Taliban arms depot. That's blood on our hands and a stain on our soul too.
So we can't be "morally pure" by just banning torture or anything that anyone might consider torture. The choice is between harsh interrogation and more deaths--enemy deaths, American deaths, and deaths of innocents in the crossfire. Do I want us imitating the way Saddam treated his victims? No. But there's a lot of room between asking nicely and clear torture. There's a trade-off to be made and reasonable disagreements over whether to draw the line. The CIA wanted it drawn just short of where we forbid torture by law and treaty when dealing with the most important Al Qaeda prisoners. Others want terrorists to get the same protections as American criminals in police custody.
One proposal that keeps coming up is "Outlaw harsh methods, but break the law in an emergency." Even John McCain's said that. I'm opposed to it.
There's a lot of areas (including my day job) where having harsh rules with vague limits constrains people much more than was originally intended. A felony conviction and a long stay in Leavenworth is something most of our defenders consider worse than dying in action. Banning harsh practices means even milder ones will be avoided if a future investigation might consider them excessive. So we'll lose out on information we could've gotten. The worst effect will be terrorists telling themselves "All I have to do is tough this one out and I'm home free, this is the worst they can do" instead of being told there's always something rougher waiting if they won't talk.
That's one danger. Let's look at how "keep it illegal and accept breaking the law in extreme cases" has worked out in another situation--criminal law enforcement. Cops aren't allowed to beat suspects up to make them talk, or break into houses without a warrant hoping to find useful evidence. They can be put on trial if they do so willfully. How well has the threat of prosecution worked to make cops behave? Hardly at all. It worked so badly that the court system completely abandoned trying to control illegal evidence gathering through prosecutions and instead created the Exclusionary Rule. Because cops could go into a courtroom and confidently put their record of service to the public against the misery of a violent scumbag knowing that no jury will take the side of the scumbag. And if the juries are that predictable prosecutors won't waste their time with a case they know will result in an acquittal.
To have a set of rules you can enforce they have to address the problem in a serious way. If a jury is told that criminals or terrorists have to be treated more gently than they discipline their own children, they're not going to take that law seriously. And if the law isn't taken seriously it's as easy to get away with huge violations as minor ones.
So we'd wind up with interrogations limited by the interrogator's expectations of how a jury would look at the case. Some will avoid a slap on the belly lest a jury think they were too violent. Others will raid the motor pool and dental clinic for tools in the belief that at least one juror will say "You do what you gotta do." The responsibility for both errors will have been evaded by those with the Constitutional duty to protect the nation.
What I'd suggest is a specified set of methods which can be authorized by different levels of the chain of command. So interrogators would have standard rules but could request permission from the local commander to use stress positions or 72 hours of sleep deprivation. If that doesn't work the regional boss could authorize slaps, grabs, and "walling." Next would be the Deputy Director in DC's permission for extended standing or hypothermia. The Director of the CIA could authorize waterboarding with plastic wrap over the face (no water in the lungs) and unconventional methods such as dropping bugs on someone phobic. Requests for anything more severe would have to go to the President, who has to decide whether they were "harsh" (and permitted) or forbidden torture.
That gives interrogators the option of always being able to escalate in the worst case. The rules would be clear so they wouldn't be limiting themselves in fear of an unjustified prosecution. If they do go over the line they've broken a direct order from a superior, a much easier issue to prosecute. The responsibility for methods is always clear. That would give the best balance between unnecessary harshness and unnecessary deaths.