Jeffrey Goldberg, The Atlantic (via Think Progress):
[McCain] told me of his fundamental disagreement with Cheney: "When you have a majority of Americans, seventy-something percent, saying we shouldn't torture, then I'm not sure it helps for the Vice President to go out and continue to espouse that position," he said. "But look, he's free to talk. He's a former Vice President of the United States. I just don't see where it helps."
And then he got acerbic: Cheney, he says, "believes that waterboarding doesn't fall under the Geneva Conventions and that it's not a form of torture. But you know, it goes back to the Spanish Inquisition."
Notes TP, "Yesterday on FOX News, McCain reiterated that waterboarding is 'not a new technique, and it is certainly torture.' 'You hear it from al Qaeda operatives that when we torture people and it becomes public, then it helps them recruit,' he said."
Dick would argue that this is the reason why it shouldn't become public. More logical people would argue that it's just one more reason why we shouldn't torture -- if we've learned anything here that everyone can agree on, it's that you can't do this stuff and keep it under wraps.
Other good reasons are that it's sick, illegal, and evil. History remembers no society that we congratulate for their torture.