On The American Street, Mark Kleiman quotes Phil Carter on the limits of torture, as applied to Candaian Maher Arar, who the US tortured by proxy, by shipping him off to Syria (where he was also a citizen, but hadn't been for years):

Carter explains how much could have been done to Arar while remaining within the letter of the promise not to "torture" him:

Locking someone in a small cell, denying him access to the outside world, etc. -- those are all "coercive" techniques, but they may or may not be torture. (See Mark Bowden's article in the Atlantic Monthly for where this line is drawn.) The importance of this distinction is that international law outlaws torture, but it does not outlaw coercion. Moreover, it does not tell a nation what it can do with its own nationals, because that would be an intrusion on state sovereignty.

Arar claims Syria went well over this line -- but forget that. Just consider that when hearing that in the jails in Baghdad at Guantanmo, in the cells full of prisoners that the US will not name, we are not using torture.

And then consider allegations (like those featured on the front of the Wall Street Journal yesterday, unfortunately not free on line) that we too have gone over that line...