I can't for the life of me figure out why anyone in this day and age thinks torture is effective for anything other than inflicting emotional and physical pain on a subject.
Torture is taking a US military TA-312 phone and running the bare-wire ends from it to a captured enemy's testicles and then cranking the phone, sending an electrical charge down the wires, in order to get him to talk.
The Pakistanis torture men and women by lowering them down onto a rounded-end steel rod so that the rod slides into the rectum, and then very slowly lowering them further still, all the while telling them it's in their best interests to talk. The world is full of torture techniques employed by governments and militias and the like. Not sure that waterboarding actually constitutes "torture" in the real sense, though I agree on it being classified as "enhanced interrogation."
Whether waterboarding actually works or not is also up for debate. Some say it does and others maintain it doesn't. From what I understand, interrogators had to waterboard Khalid Sheikh Mohammed, the operational planner behind the 9/11 attacks, something like 186 (or 156, I forget which) times before he finally spilled his secrets. Other detainees proven to have participated in the 9/11 planning and attack or support phases cracked after only a single session or 2 or 3 of them.
US military personnel being trained in survival, evasion, resistance and escape (SERE) are also subjected to a technique that's similar to waterboarding, by the way.
Whether waterboarding is actual torture or not appears to be a matter of one's ideology, it seems to me.