Now that so many sad truths about Afghanistan are being spoken aloud, even in the major media — let me add one more: The war, from start to finish, was about politics, not in Afghanistan but in the United States.

Afghanistan was always a sideshow. According to the official account, the Sept. 11, 2001, terrorist attacks were launched from U.S. soil, by people who trained in Florida. Most of the named perpetrators were Saudis. Al-Qaida leader Osama bin Laden had made his base in Afghanistan after leaving Sudan; soon he went on to Pakistan, where he stayed for the rest of his life. Afghanistan’s Taliban rulers were not accused of having been involved in the 9/11 attacks.

But the 2001 invasion was fast and apparently decisive. And so it rescued George W. Bush’s tainted presidency, which was teetering just then from a defection (by James Jeffords of Vermont) that had cost Republican control of the Senate. Bush’s approval shot up to 90% and then steadily declined, though two additional boosts — following the invasion of Iraq in March 2003 and the capture of Saddam Hussein in December — got him, barely, through the 2004 election.