Recently de-classified documents (open a pdf of the documents) now prove, definitively, that the Bush Administration lied about when - and how - they came to the conclusion that Iraq was an "imminent threat" and therefore, the effort in Afghanistan had to be put on the back burner. In a meeting in November 2001 between Defense Secretary Donald Rumsfeld and CENTCOM Commander Tommy Franks, the two began fleshing out their made up rationale for invading Iraq.
As you can see from the picture above, in the section entitled "How start?" Rumsfeld came up with three potential rationales for an invasion (each phrased in the form of a question): 1) Saddam moves against Kurds in the North? 2) US discovers Saddam connection to 9/11 attacks or to anthrax attacks? 3) Dispute over WMD inspections? -- Start now thinking about inspection demands.
There you go, folks. Despite the Bush Administrations claims that a decision to go to war in Iraq was not made until days before the invasion, and that they did "everything" they could to avoid war, the decision had been made shortly after the 9/11 attacks. Even though the Administration knew with 100% certainty that Saddam Hussein was not involved with 9/11, they were still floating the idea of saying he was to justify the invasion. And before there were any WMD inspections, Rumsfeld was already set to "dispute" the findings when they eventually happened. Note also how the idea of taking troops out of Afghanistan and moving them to Iraq was put into place here, as well.
The entire thing was based on a lie. That is not this, or any other, writer's opinion. There it is in black and white from the administration itself. Spin away, righties.