The only physical evidence the administration offered for an Iraqi nuclear program were the 60,000 aluminum tubes that Baghdad set out to buy in early 2001; some of them were seized in Jordan. Even though Iraq had a history of using the same tubes to make small rockets, the president and his closest advisers told the American people that the overwhelming consensus of government experts was that these new tubes were to be used to make nuclear bomb fuel. Now we know there was no such consensus. Mr. Bush's closest advisers say they didn't know that until after they had made the case for war. But in fact, they had plenty of evidence that the claim was baseless; it was a long-discounted theory that had to be resurrected from the intelligence community's wastebasket when the administration needed justification for invading Iraq.
The New York Times: The Nuclear Bomb That Wasn't