This recent story from the Washington Post is probably relevant to the discussion here.
When CIA officials subjected their first high-value captive, Abu Zubaida, to waterboarding and other harsh interrogation methods, they were convinced that they had in their custody an al-Qaeda leader who knew details of operations yet to be unleashed, and they were facing increasing pressure from the White House to get those secrets out of him.
The methods succeeded in breaking him, and the stories he told of al-Qaeda terrorism plots sent CIA officers around the globe chasing leads…
Abu Zubaida’s revelations triggered a series of alerts and sent hundreds of CIA and FBI investigators scurrying in pursuit of phantoms. The interrogations led directly to the arrest of Jose Padilla, the man Abu Zubaida identified as heading an effort to explode a radiological “dirty bomb” in an American city. Padilla was held in a naval brig for 3 1/2 years on the allegation but was never charged in any such plot. Every other lead ultimately dissolved into smoke and shadow, according to high-ranking former U.S. officials with access to classified reports.
“We spent millions of dollars chasing false alarms,” one former intelligence official said.
Despite the poor results, Bush White House officials and CIA leaders continued to insist that the harsh measures applied against Abu Zubaida and others produced useful intelligence that disrupted terrorist plots and saved American lives.