Britain's Prime Minister Tony Blair pictured at Chequers in February 2003, the month the note to George Bush was written.
The February 2003 memo, declassified as part of the Chilcot Inquiry into the Iraq war, shows the Machiavellian scheming of the former Labour Prime Minister, who seems more concerned with bringing public opinion round to the idea of war than Iraq's actual weapons disarmament.
The note to George Bush begins with a warning that public opinion in Europe is against the invasion of Iraq, as are some European governments such as France.
Blair complains that the public and the press see Hussein's "passive" cooperation with weapons inspections, i.e. letting inspectors into the country, as good enough. Blair believes Hussein must "actively" help: point out where weapons may be.
Blair proposes a "trick" to bring public opinion and reluctant governments on-side: tabling a new UN resolution that will give Saddam a new ultimatum on cooperation. If he fails to comply, then surely the public and the international community would see that the US and UK have done all they could and military action is the only option.
It's not the first time Blair floated this idea. As early as July 2002 he was talking about using Saddam theoretically breaking UN resolutions as "our casus belli" - a Latin phrase that means an action that justifies war.
Incredibly, Blair said in the February 2003 memo that a disadvantage of this tactic is Saddam "might conceivably comply fully" with the UN weapon's inspection resolution.
This seems to undermine Blair's central argument to Parliament and the public about justifying the war in Iraq: that Saddam had weapons of mass destruction that threatened the UK and Europe. If he had had weapons, wouldn't full cooperation with UN demands to inspect them be a step in the right direction towards peaceful disarmament?
In reality, it seems Blair simply saw Saddam as a bad actor in the Middle East who had to be removed. In the 2002 memo to Bush, he said that: "Getting rid of Saddam is the right thing to do."
Blair wrote in the 2003 memo that another disadvantage of going down the UN ultimatum route is that it could "delay the start of military action by a week." No wonder the public thought he was "hell bent" on war.
One of the advantages of the UN resolution strategy, Blair said, is that: "It allows us to show the world we are going to war, not because we want to, but because we have to."
But despite Blair's assertion that "we are going to war", he insisted in the next paragraph that pursuing another UN resolution would show the US and UK "went the last mile for peace."
Blair said he had "never come across an issue in which the dividing line between overwhelming support and overwhelming opposition is so slender."
He concluded: "The only explanation is that they need to be persuaded that we would prefer peaceful disarmament if that were possible. Proving it isn't possible is the huge benefit of the ultimatum route."
Of course, it may well be the case that Saddam would have never fully complied with disarmament to the standards Blair demanded. But his earlier claim that Saddam fully complying with the ultimatum would actually have been a disadvantage shows that he wasn't really committed to "peaceful disarmament" but wanted to get rid of Saddam.
Blair comes across as the master chess player who sees 10 moves ahead. He knew where he wanted to get to and tried to arrange the board so he could get there. The pieces he played with were public opinion, the UN security council, ultimatums on weapons inspections, and intelligence about WMD capabilities.
Blair concluded the 6-page memo by saying: "We need to start firming up the humanitarian work for the aftermath of the conflict."
Less than a month later Parliament approved war in Iraq and a month and a day after Blair penned the memo the invasion of Iraq began.
The Chilcot Report, published after a 7-year inquiry, concluded that the UK committed to war in Iraq "before peaceful options were exhausted" and was based on "flawed intelligence."