The problem with any arguments for regulated torture is the question of who gets to decide when it's appropriate. Who decides when the stakes are high enough for torture? Who decides when to discard the notion of innocence until proven guilty? In all cases, the government decides.
The government, being made up of fallible men and women, would then be given the power to declare a threat and then abuse its citizens on the basis of that declaration. This situation is completely unacceptable in a free society and would overturn everything that distinguishes Western societies from the terrorists.
(Published in The Australian, Letters to the Editor, 8 January 2008)