Ethically speaking, waterboarding is torture. It is little different than when any fascist regime has procured false confessions or intelligence by dunking a person's head in a basin of water, only to remove it at the brink of suffocation. That they are strapped down to a board and we have finer control over the stimulus makes no difference. It's distressing to the person because they believe their life to be in imminent danger. I am not interested in whether or not the U.S. has the so-called right to do it, or that it's called "enhanced interrogation" or torture. The minutiae are irrelevant. The U.S. can do whatever it wants... it has proven that now. Anything that can happen, does happen. Waterboarding is just one thing the public is aware of.
My beef is that the U.S. tries to portray itself as the good guy, the nation that spreads freedom and democracy, humanitarian principles, etc. It is rather two-faced to sign the Geneva Convention on Torture and make grandiose speeches treating people properly, only to turn around and take enemies, without legal recourse, to some concealed gray zone in the Caribbean. All that does is reek of hypocrisy and it has - whether or not those in favour of waterboarding want to admit it - left a black mark on the reputation of the U.S. as a savior of the oppressed.
If you're going to put people under such duress, then just be up front about it. The USSR did it, China does it to dissidents, and I'm sure some European countries do it in their intelligence communities. Just stop acting so righteous about it, as though your tortures are different from some other nation's. You are no different than they are, regardless if you feel justified in doing it.
It is a shining example of why U.S. foreign policy is a complete and utter hypocrisy. Do as I say, not as I do.