[Just another Joe]

How is it, then, that you can consider the collateral damage done to civilians during a war, fair game, but not the deliberate inflicting of pain, on someone actively targeting civilians in an Undeclared war?

You just said it.
The collateral damage done civilians in a state of declared war is not torture, per se.
Even spies are not tortured. They are given a trial and killed outright.
I wouldn't condone torture in a declared war, why would I condone it in an undeclared war?

[hobbes1]

Because DECLARED wars seek to avoid killiing mommies daddies and children, whereas Terrorists do not.

So, the choice is Torture, or risking more innocent lives. Simple as that.

The Chance of another Terror incident, and the amount of time a terrorist is allowed to hold information are DIRECTLY PROPORTIONAL.