Some of the spinners are more carefully misleading about this; here's Powerline today

[Wilson] was to determine whether Iraq had attempted to purchase yellowcake, an essential ingredient for nonconventional weapons.

They don't say nuclear, because of course that would raise the technical baggage in terms of a claim that could be justified.

Thanks for bringing attention this, Matt, as it has always infuriated me. It took a collection of some of the world's best chemists and physicists,and the building of an entire (huge) national laboratory, Oak Ridge, to produce enough enriched uranium for a pair of atomic bombs. It still takes that laboratory with its massive enrichment apparatuses a fair bit of time and money - not to mention electricity - to make enough material for a bomb. That's with a whole science infrastructure that supports advanced in that kind of technology, which Iraq simply did not have.  And making weapons-grade enriched uranium is a lot more enrichment (about 5 to 10 times more) than just making it for a nuclear reactor. So it's a pretty serious engineering operation to do this type of enrichment, and that's one of the reasons that weapons inspectors are so successful at finding nuclear weapons.

The idea that Saddam could just magically turn yellowcake into a bomb was always absurd, and I'd be surprised if an old DoD vet and cold war hawk like Cheney hadn't been told that many, many times.  The whole yellowcake business was pretty cockamamy to begin with.

The argument contained in the "16 words" (and it may have been an inference, only) was that by seeking uranium Saddam was evidencing his continuing intention to obtain nuclear weapons.

The form of that uranium was not relevant to the argument.

The form was, however, relevant in judging whether the statement was true.  In other words should we believe that Saddam, who had plenty of uranium in Iraq, already, would be purchasing more.

Isn't this typical of this administration?  They can't even tell their lies competently!

I can see the administration picking this up and running with it, regardless of whether it was true, plausible, or polka-dotted.

You could make the argument that Cheney and Rice going on television and saying "boo!  mushroom clouds!" had more of an effect on people than any 16 words in the State of the Union.  But this would be splitting hairs.

The threat was hyped, our stated process of "forcing Saddam to disarm" was just a cover story for going in and "taking him out."

Keep it simple!

The Dept of Energy has the experts in turning uranium into the input for a nuclear weapon.  They oversee the job for the US weapons.

By my memory,
DOE did the initial analysis and raised all the logical and logistical arguments about why it made no sense to see the uranium in terms of risk to US

DOE folks were part of the intelligence community analysis but when the final version got put together, DOE was represented by a non-nuclear expert who did not push for the DOE experts' views.

So this was another avenue of expertise closed off in the final intelligence reporting.

FYI - Iraq had/going to have uranium is of so little risk and probability as to be neglibile.  The US faces a far greater risk and probability of a country or group getting the materials from the former Soviet Union (Rusia and countries in old SU) than Iraq.  (Sam Nunn and company are fierce advocates for getting those materials out of the old Soviet Union since they are so poorly secured.
But nuclear materials in the old SU did not fit the preconceived anti Iraq planning.

Your analogy is too simplistic.

The point here is that to get from yellowcake to a working bomb takes about a million steps, not 5.

And the Bush Administration was trying to tell us that Saddam was at step 999,997 while in fact they were only at step #2.

(Oh, it turned out that even THAT wasn't true. They hadn't even tried to buy the the "macaroni"!)

I'm sorry "stuff they had in the 80s".

I'm sorry, but Matt and Brendan Koerner don't have it quite right either.

I do think that if one is going to comment on the science, one should take some time to learn what the science is.

Some of the previous comments come close, but none of them is quite right either.

The analogy of the macaroni is correct: without yellowcake or equivalent, you can't get the fissionable material for a nuclear weapon.

It's also correct that you need quite a few steps to go from yellowcake to the metallic U-235 that is part of a nuclear weapon.

The Koerner article isn't quite wrong, but it isn't quite right, either. "The precious radioactive element" could refer to U-238 or U-235 in the context. The following percentages then refer to total uranium, which could be "the precious radioactive element."
Yes, UF6 "can easily be turned into a gas," by heating, but that's not the most notable feature of that whole step. The general confusion in most popular accounts between physical and chemical transformations further muddies this sentence.

The article reads like Koerner got an explanation from Matt Bunn (who I would expect to know this stuff), didn't understand it, and did his best to write it up for Slate.

Then Yglesias doesn't quite understand what Koerner is saying, so he can say stuff like

the yellowcake Saddam didn't buy from Niger wasn't the right stuff anyway:

The right stuff for what? If Saddam had the right facilities, it was the right stuff. Metallic U-235 would have been better, yes. A fully operational nuclear weapon stolen from a nuclear power would be better still.

The seriousness of the Niger forgeries lies elsewhere. It's not improbable that Saddam would have tried to get unaccountable uranium (unlike that at Tuwaitha) for a program. It's more improbable that Niger would have sent it to him.

This whole thread is irrelevant to the leak investigation. If you don't understand the science, don't try to discuss it.