From Jonathan Landay at McClatchy, one of the few reporters to get the story right during the march to war:

The Bush administration put relentless pressure on interrogators to use harsh methods on detainees in part to find evidence of cooperation between al Qaida and the late Iraqi dictator Saddam Hussein’s regime, according to a former senior U.S. intelligence official and a former Army psychiatrist.

Such information would’ve provided a foundation for one of former President George W. Bush’s main arguments for invading Iraq in 2003. No evidence has ever been found of operational ties between Osama bin Laden’s terrorist network and Saddam’s regime.

The use of abusive interrogation — widely considered torture — as part of Bush’s quest for a rationale to invade Iraq came to light as the Senate issued a major report tracing the origin of the abuses and President Barack Obama opened the door to prosecuting former U.S. officials for approving them.