These are the questions raised in "Taxi to the Dark Side," a troubling documentary from Alex Gibney ("Enron: The Smartest Guys in the Room").
Gibney goes back to the first days of the invasion of Afghanistan, and reconstructs (using independent interviews with our own soldiers) conditions in prisons where suspected terrorists/al Qaeda/Taliban were held.
The thrust of Gibney's documentary is that the Bush administration intentionally established murky rules for tactics interrogators could use - some violence was acceptable, and so some violence was used.
These harsh tactics led to some early successes - high-value prisoners yielded useful information. Which, of course, led to more vigorous application of rough tactics, and that's when the problems started.
The United States offered bounties for suspects, and Afghan warlords started grabbing civilians off the streets, more interested in collecting money than in finding actual terrorists.
Gibney cites the case of Diliwar, a Kabul taxi driver mislabeled as a high-value detainee, sent to prison where he was denied sleep and beaten until the bruises and internal bleeding killed him. (The military's own investigators say that 37 botched interrogations have now been classified as homicides.)
He was part of a big second wave of low-value and no-value detainees, also subjected to harsh tactics. The flow of information dried up, but the pressure to produce results remained. Innocent Afghans paid the price.
And so, we see, did our soldiers. The United States investigated Diliwar's case (and others), and found soldiers guilty of various charges. Some were discharged, some sent to military prison. Gibney positions this not as justice, but as another outrage.