The debate over Guantanamo usually slides immediately into the moral dilemma of whether it’s permissible to abuse or “torture terrorists.” It’s an important debate but it obscures a basic flaw: many of them weren’t terrorists.
The moral contours become a bit different when the question becomes “Is it ok to torture people who aren’t terrorists?” Not that much fo a close call, is it? But it’s been very hard to get a real sense of whether non-terrorists were a rare exception caught up in the dragnet or a larger group.
That’s why this piece by Lawrence Wikerson is one of the most important essays I’ve seen in the last eight years on this topic. Read the whole piece. Wilkerson was chief of staff to former Secretary of State Colin Powell and therefore had a high level, inside perspective.
The gist is that many of those held at Guantanamo had no connection to terrorism, the administration knew that, and very little useful inteligence came out of the operation:

“No meaningful attempt at discrimination was made in-country by competent officials, civilian or military, as to who we were transporting to Cuba for detention and interrogation.
This was a factor of having too few troops in the combat zone, of the troops and civilians who were there having too few people trained and skilled in such vetting, and of the incredible pressure coming down from Secretary of Defense Donald Rumsfeld and others to “just get the bastards to the interrogators”….
Several in the U.S. leadership became aware of this lack of proper vetting very early on and, thus, of the reality that many of the detainees were innocent of any substantial wrongdoing, had little intelligence value, and should be immediately released. …The fact that among the detainees was a 13 year-old boy and a man over 90, did not seem to faze either man, initially at least….
[“Mosaic philosophy”] held that it did not matter if a detainee were innocent. Indeed, because he lived in Afghanistan and was captured on or near the battle area, he must know something of importance (this general philosophy, in an even cruder form, prevailed in Iraq as well, helping to produce the nightmare at Abu Ghraib). All that was necessary was to extract everything possible from him and others like him, assemble it all in a computer program, and then look for cross-connections and serendipitous incidentals–in short, to have sufficient information about a village, a region, or a group of individuals, that dots could be connected and terrorists or their plots could be identified.

Thus, as many people as possible had to be kept in detention for as long as possible to allow this philosophy of intelligence gathering to work. The detainees’ innocence was inconsequential. After all, they were ignorant peasants for the most part and mostly Muslim to boot….
Even for those two dozen or so of the detainees who might well be hardcore terrorists, there was virtually no chain of custody, no disciplined handling of evidence, and no attention to the details that almost any court system would demand. Falling back on “sources and methods” and “intelligence secrets” became the Bush administration’s modus operandi to camouflage this grievous failing….
In addition, it has never come to my attention in any persuasive way–from classified information or otherwise–that any intelligence of significance was gained from any of the detainees at Guantanamo Bay other than from the handful of undisputed ring leaders and their companions, clearly no more than a dozen or two of the detainees, and even their alleged contribution of hard, actionable intelligence is intensely disputed in the relevant communities such as intelligence and law enforcement