Why the Downing Street Memo is important...

Via Atrios, :

Andrew Bacevich, a retired Army colonel who is now a war analyst at Boston University, said: "The memo is significant because it was written by our closest ally, and when it comes to writing minutes on foreign policy and security matters, the British are professionals. We can conclude that the memo means precisely what it says. It says that Bush had already made the decision for war even while he was insisting publicly, and for many months thereafter, that war was the last resort."

This is not hearsay. This is documentary proof.