There is only one good thing about the fact that the 20th anniversary of the Sept. 11, 2001, terror attacks will take place less than a month after the Taliban have re-established the Islamic Emirate of Afghanistan. It will serve as a reminder of why it was necessary to invade the country and topple the Taliban government two decades ago.

When nearly 3,000 people are slaughtered on your soil in an operation planned and ordered by a known terrorist group residing in a country whose government refuses to cooperate in bringing that group and its leader to justice, there are no good options. The retaliatory attack on Afghanistan was the only time Article 5 of the North Atlantic Treaty, under which signatories agree to consider an attack on one as an attack on all, was invoked. The United States-led invasion was widely supported at the time — unlike the invasion of Iraq two years later.

For these reasons, the 20th anniversary of 9/11 will be an even more somber occasion than usual. Alongside the terrible memories of that day will now stand a powerful sense of two decades of failure in Afghanistan; of the betrayal of all those Afghans who had become convinced that they could live in a freer and somewhat more prosperous country; and of a major blow to the international credibility of America, NATO and President Joe Biden personally. But while most of the recrimination focuses on what has and has not been done in Afghanistan, the real failure since September 2001 has been regional. And that failure centers on Pakistan.