1 President George Bush inserts a claim - that Saddam Hussein had been trying to buy uranium from Niger - into his State of the Union Address on 28 January 2003. He also tells Congress where the information came from: "The British government has learned that Saddam Hussein recently sought significant quantities of uranium from Africa."
The British Government still stands by its claim. But the director general of the International Atomic Energy Agency, Mohamed Al Baradei, told the UN Security Council on 7 March 2003 that the documents on which the Niger allegations were based were phoney. Another IAEA official said the flaws were so obvious "they could be spotted by someone using Google."
2 David Kay, the man in charge of America's effort to ferret out the purported weapons of mass destruction in Iraq, stepped down in January 2004, and admitted he does not expect that the munitions to be found. His departure triggers a political firestorm in the US that forces Mr Bush to embrace a formal investigation into the failures of US intelligence.
The British Government had just been let off the hook by the Hutton Report into the row between Downing Street and the BBC over reporting of WMD. But Mr Bush's decision to co-operate with the Senate report exposes Blair once again. He agrees to allow a former civil servant, Lord Butler, to instigate his own investigation into British intelligence foul-ups.
3 The report by the Senate Intelligence Committee, released last Friday, was excoriating about the CIA. The October 2002 National Intelligence Estimate "either overstated or [was] not supported by, the underlying intelligence reporting", it said.
It is horrendous timing for Mr Blair. The US report has come out just five days before the release of the Butler review. Sensing the danger, Mr Blair concedes for the first time that WMD may never be found in Iraq. Mr Blair's appointment of John Scarlett as the new head of MI6, in spite of his role in assembling UK intelligence on Iraq, is also likely to come under attack.
4 Trust in George Bush becomes a potent new theme in the US election campaign. The people are "clamouring for restoration of credibility and trust in the White House," asserts Democrat hopeful John Kerry in interviews with his new running mate, John Edwards, published in US newspapers. Iraq and the furore over faulty intelligence are the issues that allow the Democrats to ignite the trust question.
The clamour in America finds a dangerous echo in British for Mr Blair. With his popularity dropping to new lows, reports - denied by insiders - surface that the PM thought about resigning.