Just for the sake of argument: suppose it DID work

In response to the release of LOTS of documents on W-era torture, conservatives have adopted a more-or-less consistent reply: "Yeah, we tortured... BUT IT WORKED!" - We've been "safe" for 7.5 years!

Let's grant 'em the premise. Okay - it worked.
So what?

"The ends justify the means" isn't much of a basis for The Rule of Law! - let alone morality!!!

Yes - the Rule of Law imposes heavy burdens on us as a country - as a CIVLIZED nation.
BUT: the dividends it pays are immeasurable!
ANY "temporary", expedient circumvention of The Rule of Law threatens us all - more than the supposed dangers from which this circumvention "protects" us.

Recall Robert Bolt's wonderful defense of The Rule of Law from his play, A Man for All Seasons:

William Roper: So, now you give the Devil the benefit of law!

Sir Thomas More: Yes! What would you do? Cut a great road through the law to get after the Devil?

William Roper: Yes, I'd cut down every law in England to do that!

Sir Thomas More: Oh? And when the last law was down, and the Devil turned 'round on you, where would you hide, Roper, the laws all being flat? This country is planted thick with laws, from coast to coast, Man's laws, not God's! And if you cut them down, and you're just the man to do it, do you really think you could stand upright in the winds that would blow then? Yes, I'd give the Devil benefit of law, for my own safety's sake!
[emphasis added]

Give the Devil benefit of law?

Yes! - for my own safety's sake!!!