This story was reported recently, but I don't think it's gotten as much attention as it deserves. It describes conversations between President Bush and a family friend:
"Two years before the September 11 attacks, presidential candidate George W. Bush was already talking privately about the political benefits of attacking Iraq, according to his former ghost writer, who held many conversations with then-Texas Governor Bush in preparation for a planned autobiography.
“'He was thinking about invading Iraq in 1999,” said author and journalist Mickey Herskowitz. “It was on his mind. He said to me: ‘One of the keys to being seen as a great leader is to be seen as a commander-in-chief.’ And he said, ‘My father had all this political capital built up when he drove the Iraqis out of Kuwait and he wasted it.’ He said, ‘If I have a chance to invade….if I had that much capital, I’m not going to waste it. I’m going to get everything passed that I want to get passed and I’m going to have a successful presidency.'”
In other words, Bush's reason for the war in Iraq was to build, in his characteristic phrase, his domestic "political capital." This really should rank, in terms of public attention, with the Downing Street memos.