In this Jan. 5, 2006, file photo, Jose Padilla, center, is escorted to a waiting police vehicle by federal marshals near downtown Miami. (J. Pat Carter/AP)

There's all sorts of damning stuff in the just-released Senate investigation of the CIA’s secret interrogations of terrorism suspects. But one story in it really encapsulates the absurdity of the brutal interrogation methods and authorities' self-delusion about their results.

It also involves a terror plot that may well go down in history as one of the most stupid plans ever.

First, the history: The Senate report points out that one of the most referenced plots "thwarted" by secret interrogations was that of Jose Padilla and his so-called "Dirty Bomb" plot on Washington. Padilla, a U.S. citizen, had been arrested when he returned to the United States from Pakistan in 2002, and was soon accused of planning a bomb attack for al-Qaeda that would have spread dangerous radioactive material across the American capital and beyond.

The "dirty bomb" was an evocative, terrifying idea. But within two years, there were public doubts that it was ever a real threat: A 2004 Post article notes that al-Qaeda was skeptical about it and wanted Padilla to instead pursue a plan to attack tall buildings in the United States by creating natural gas explosions.

Even so, the Senate's report says the alleged plot was repeatedly held up as an interrogation success story.

The report points to a document prepared for Vice President Dick Cheney in 2005 that argued that the dirty bomb plot had been "disrupted" by "DOJ-authorized enhanced interrogation techniques." A 2007 memo from the Department of Justice Office of Legal Counsel (OLC) also said the techniques helped to find "two al-Qaeda operatives already in the United States and planning to destroy a high rise apartment building and to detonate a radiological bomb in Washington, D.C."

The Senate report states that both the dirty bomb plot and related tall buildings plot were invoked by the CIA as "thwarted" following the use of these interrogation methods as recently as 2009.

There are two major problems with that argument. First, the report notes, the information that led to the arrest of Padilla and his accomplices was acquired before these techniques were implemented. Here's how the report describes it:

CIA records indicate that: (1) there was significant intelligence in CIA databases acquired prior to — and independently of — the CIA's Detention and Interrogation Program to fully identify Jose Padilla as a terrorist threat and to disrupt any terrorist plotting associated with him; (2) [high profile al-Qaeda facilitator] Abu Zubaydah provided information on the terrorist plotting of two individuals who proposed an idea to conduct a "Dirty Bomb" attack, but did not identify their true names; (3) Abu Zubaydah provided this information to FBI special agents who were using rapport-building techniques, in April 2002, more than three months prior to the CIA's "use of DOJ-approved enhanced interrogation technique.

Ali Soufan, one of the FBI agents who interrogated Abu Zubaydah, has provided accounts of how he got the information about the dirty bomb plot from Abu Zubaydah. In a New York Times op-ed in 2009, Soufan notes that Padilla was arrested in May, before the interrogation methods were implemented. He later told Newsweek that Abu Zubaydah had opened up about the plot after he gave him a Coca-Cola. (Abu Zubaydah's later interrogation — which included waterboarding and keeping him in coffin-sized boxes — was so harsh that CIA employees at a secret site in Thailand themselves broke down.)

The second problem with the claim is that the dirty bomb plot would never, ever have worked. According to a 2003 CIA e-mail, Padilla and his alleged accomplice, Binyam Mohammed, had apparently taken seriously an Internet article that offered laughable instructions for creating an "H-Bomb." That article is still easy to find online, and is clearly tongue-in-cheek. It begins with the phrase: "Making and owning an H-bomb is the kind of challenge real Americans seek." It goes on to instruct those hoping to make a bomb to fill buckets with uranium and swing them above their head "as fast as possible."

U.S. experts were certain that such a plan would cause death — but not to the public. Here's how an internal CIA e-mail described it in 2003:

CIA and Lawrence Livermore National Lab have assessed that the article is filled with countless technical inaccuracies which would likely result in the death of anyone attempting to follow the instructions, and definitely would not result in a nuclear explosion.

According to the CIA report, Padilla and Mohammed later told investigators that the dirty bomb plot was a ruse to get out of Pakistan and avoid fighting in Afghanistan. It doesn't seem to have been taken seriously by al-Qaeda at any point.

In 2005, the chief of the CIA's Counterterrorism Center CBRN (Chemical, Biological, Radiological and Nuclear) Group mocked the dirty bomb plan and its subsequent trumpeting by the CIA. In an article titled "Don't Put All Your Uranium in One Bucket," he wrote:

[O]nce again I'd like to go on the record that Padilla admitted that the only reason he came up with so-called 'dirty bomb' was that he wanted to get out of Afghanistan and figured that if he came up with something spectacular, they'd finance him. Even [Khalid Sheik Mohammed] says Padilla had a screw loose. He's a petty criminal who is well-versed in US criminal justice (he's got a rap sheet as long as my arm). Anyone who believes you can build an [improvised nuclear device] or a [radiological dispersal device] by 'putting uranium in buckets and spinning them clockwise over your head to separate the uranium' is not going to advance al-Qaida's nuclear capabilities.

Padilla was never charged with the dirty bomb plot, and instead eventually faced charges of conspiracy to murder, kidnap and maim people abroad, conspiracy to provide material support for terrorism and providing material support for terrorism. Binyam Mohammed, a British citizen, was released in 2007 after being held in Guantánamo Bay and alleges that he was tortured by the U.S.

There are plenty of more horrifying details in the Senate report. But it's hard to summon a better example of the absurdity than the dirty bomb fiasco. Not only had the CIA bragged that its enhanced interrogation techniques had foiled a nuclear plot when in fact friendly rapport-building techniques had – but the plot itself was far too stupid to ever work.