Seymour Hersh in the New Yorker via Susie:

The Administration’s planning for a military attack on Iran was made far more complicated earlier this fall by a highly classified draft assessment by the C.I.A. challenging the White House’s assumptions about how close Iran might be to building a nuclear bomb. The C.I.A. found no conclusive evidence, as yet, of a secret Iranian nuclear-weapons program running parallel to the civilian operations that Iran has declared to the International Atomic Energy Agency. (The C.I.A. declined to comment on this story.)

Well, let's be reasonable here, people. It's not like our fundamentally serious administration could ever be wrong about a program to develop weapons of mass destruction in a middle eastern country whose name begins with the letter "I," right?

he C.I.A.’s analysis, which has been circulated to other agencies for comment, was based on technical intelligence collected by overhead satellites, and on other empirical evidence, such as measurements of the radioactivity of water samples and smoke plumes from factories and power plants. Additional data have been gathered, intelligence sources told me, by high-tech (and highly classified) radioactivity-detection devices that clandestine American and Israeli agents placed near suspected nuclear-weapons facilities inside Iran in the past year or so. No significant amounts of radioactivity were found.

Not that Cheney and the rest of the neo-cons really want evidence, of course:

Cheney and his aides discounted the assessment, the former senior intelligence official said. “They’re not looking for a smoking gun,” the official added, referring to specific intelligence about Iranian nuclear planning. “They’re looking for the degree of comfort level they think they need to accomplish the mission.”

"Comfort level"? What does "comfort" mean? More contracts for Halliburton?

And, for some reason, the Israelis seem just as anxious to provide the administration with "comfort" as the administration is anxious to achieve it:

As the C.I.A.’s assessment was making its way through the government, late this summer, current and former military officers and consultants told me, a new element suddenly emerged: intelligence from Israeli spies operating inside Iran claimed that Iran has developed and tested a trigger device for a nuclear bomb. The provenance and significance of the human intelligence, or HUMINT, are controversial. “The problem is that no one can verify it,” the former senior intelligence official told me. “We don’t know who the Israeli source is. The briefing says the Iranians are testing trigger mechanisms”—simulating a zero-yield nuclear explosion without any weapons-grade materials—“but there are no diagrams, no significant facts. Where is the test site? How often have they done it? How big is the warhead—a breadbox or a refrigerator? They don’t have that.”

And--they've forgotten nothing, and learned nothing--the White House is cherrypicking and stovepiping the Israeli intelligence:

the White House had asked to see the “raw”—the original, unanalyzed and unvetted—Israeli intelligence. Such “stovepiping” of intelligence had led to faulty conclusions about nonexistent weapons of mass destruction during the buildup to the 2003 Iraq war.

Splendid....

The whole article is great, and has plenty more analysis, realpolitik, etc. Go read.

NOTE Meanwhile, the neo-con drumbeat for more war continues.