And how do we know we're not wasting time by torturing the wrong guy? It's just implausible on its face, which is more than enough to dismiss the argument.
But I've got another scenario which may be worth considering.
Let's say that we have a President who is hell-bent, for heaven knows what reason, on invading Iraq. And let's say that he gets a hold of an al-Qaeda terrorist --- perhaps even a legitimate one, just to make the argument better. And let's say that the guy is tortured, using tactics modeled on the old Communist techniques which were deliberately designed to induce false confessions. And let's say that under this malign influence, the guy coughs up a wholly implausible story about connections between Iraq and al-Qaeda --- one which is implausible on its face (bin Laden having denounced Saddam repeatedly), one with no corroborating evidence, one which is flatly contradicted by two other people within al-Qaeda, with whom he had close contact. And let's say that this evidence is used as part of a campaign to stampede the country into a ruinous war which kills 2000 Americans and ruins our reputation across the world.
Implausible, I know, but no more so than the "ticking bomb" story. And it suggests that there are scenarios where there is, perhaps, something just a bit wrong with torture and its advocates.
And hey, it's still more plausible than stories of Americans subjecting prisoners to religiously tinged abuse, from the apparent death by crucifixion of one detainee to the reports of others being thrown to lions, as if the whole thing was part of the rituals of some demented cult...