For the last five years, New York Times journalist James Risen has been embroiled in a legal battle with the Obama administration over his refusal to reveal an inside government source. While that case (and the motivations behind it) is compelling, the leaked story that got Risen in trouble in the first place is one of the most spectacular CIA screw-ups in the agency's history.

The full excerpt was published in The Guardian in 2006.

In February 2000, the CIA went forward with a covert operation called Operation Merlin to stunt the nuclear development of Iran by gifting them a flawed blueprint of an actual nuclear weapon.

It all started when the CIA convinced a defected Russian nuclear engineer (who was granted citizenship and a $5,000 per month income) to hand over technical designs for a TBA 480 high-voltage block or "firing set" for a Russian-designed nuclear weapon. The designs would allow the holder to build the mechanism that triggers a nuclear chain reaction, one of the most significant hurdles to successfully building a nuclear weapon.

The plan was for the Russian to pose as a greedy scientist trying to sell the designs to the highest bidder, which was to be Iran. The Russian was sent to Vienna to sell the designs to the Iranian representative of the International Atomic Energy Agency (ie,the UN body created to regulate nuclear technology). The key to the plan was that the designs supposedly carried a serious design flaw that the Iranians would be unable to recognize, until they had already tried building the design. When the Iranians tested the design, the bomb would fizzle and Iran would have been set back years in its nuclear quest. At the same time, the US would be able to watch what the Iranians did with the blueprints and learn more about what they knew of nuclear technology.

Reuters It all sounded like a fine plan except for the fact that it was wildly reckless and included a number of huge missteps. The first was that, within minutes of looking at the plans, the Russian identified the design flaw. Granted he was more versed in nuclear designs than the Iranians he was giving the designs to, but CIA officers were shocked: they didn't expect him to be able to find it.

The CIA went forward with the plan anyways, handing the Russian a sealed envelope with the blueprints and instructing him to deliver them without opening the envelope. The Russian got cold feet and, of course, opened the envelope. Not wanting to be caught in the crossfire between the CIA and Iran, the Russian included a letter noting that the designs contained a flaw and that he could help them identify it.

The Russian dropped off the blueprints at the agreed location, without ever even meeting the officials from Iran and fleeing back to the US. Within days, the Iranian official in Vienna headed home, likely with the blueprint.

What makes the operation so reckless is that according to former CIA officials that Risen spoke to, the "Trojan horse" plan had been used before with America's enemies, but never with a nuclear weapon. Handing over any weapons designs is a delicate operation and any additional information could result in the county accelerating its weapon's program, not stunting it.

Between Iran's stable of knowledgeable nuclear scientists and the fact that the country had already obtained nuclear blueprints from a Pakistani scientist, giving them even flawed designs was extremely reckless. According to Risen, nuclear experts say that Iran could compare the two blueprints to identify the flaw and then glean dangerous information from the blueprints anyways.

Operation Merlin failed on all accounts. Add in the fact that four years later, the CIA screwed up again, revealing its entire Iran spy network to a double agent, and the US was flying blind on Iran during a period when the country was likely making serious in-roads on their nuclear program.

Check out Risen's more detailed account of this fascinating episode in the CIA's history here.