We can learn a few lessons from the recent revelations that the CIA destroyed tapes showing torture:
1. Giant, powerful intelligence agencies tend to ignore government oversight and end up being an anti-democratic force. The CIA was explicitly asked in Congress if it had any such tapes and said (before the tapes were destroyed) that it didn't.
2. The CIA, like our current government, isn't above making the most boldfaced lies. The idea that the tapes had to be destroyed "for security purposes" is LUDICROUS. It's possible to put the tapes in a vault in Langley and not allow anyone but the head of the CIA (and members of the Congressional oversight committee who request them) to see them. The "security" is a reflection by the CIA that what they're doing is illegal and so needs to be hidden.
3. It isn't wise to give any government organization too much power--particularly when it repeatedly avoids oversight and engages in cover-ups.
4. Last but not least, the claim that waterboarding isn't torture leads us to some interesting dilemmas. Should the U.S. compensate the families of the Japanese intelligence operators who were hung after WWII for using waterboarding on U.S. prisoners of war? (If it's just a "frat boy" sort of thing, the Americans who were waterboarded should be more understanding, don't you think?)