Asked directly if the war had been worth it, Mr. Gates replied, “It really requires a historian’s perspective in terms of what happens here in the long run.”

The war, he added, “will always be clouded by how it began,” — that is, he said, the premise on which it was justified, Saddam Hussein’s unconventional weapons, which did not exist. “This is one of the reasons that this war remains so controversial at home,” he said.

Bill Kristol and Max Boot had gracious reactions to the Obama speech, saying that it was really as far as an antiwar politician can go in terms of generosity to the war’s premises, from their perspective. Something similar is at work with Gates. For someone who served Presidents Bush and Obama, acknowledging the maculate origins of the war; working to mitigate its disasters; and then gradually extricating the U.S. from it — with humility and wisdom and perseverance; without avarice — is more than just as far as one can go. It’s statesmanship.