Andrew Sullivan in The Atlantic:
Dear President Bush,
We have never met, and so I hope you will forgive the personal nature of this letter. I guess I should start by saying I supported your presidential campaign in 2000, as I did your father’s in 1988, and lauded your first efforts to wage war against jihadist terrorism in the wake of 9/11. Some of my praise of your leadership at the time actually makes me blush in retrospect, but your September 20, 2001, address to Congress really was one of the finest in modern times; your immediate grasp of the import of 9/11—a declaration of war—was correct; and your core judgment—that religious fanaticism allied with weapons of mass destruction represents a unique and new threat to the West—was and is dead-on. I remain proud of my support for you in all this. No one should forget the pure evil of September 11; no one should doubt the continued determination of an enemy prepared to slaughter thousands in cold blood in pursuit of heaven on Earth.
Of course, like most advocates of the Iraq War, I grew dismayed at what I saw as the mistakes that followed: the failure to capture Osama bin Laden at Tora Bora; the intelligence fiasco of Saddam’s nonexistent stockpiles of weapons of mass destruction; the failure to prepare for an insurgency in Iraq; the reckless disbandment of the Iraqi army; the painful slowness in adapting to drastically worsening conditions there in 2004–06; the negligence toward Afghanistan.
These were all serious errors; but they were of a kind often made in the chaos of war. And even your toughest critics concede that, eventually, you adjusted tactics and strategy. You took your time, but you evaded catastrophe in temporarily stabilizing Iraq. I also agree with the guiding principle of the war you proclaimed from the start: that expanding democracy and human rights is indispensable in the long-term fight against jihadism. And I believe, as you do, that a foreign policy that does not understand the universal yearning for individual freedom and dignity is not a recognizably American foreign policy.
Yet it is precisely because of that belief that I lost faith in your war.
More here.