One thing has been sorely lacking from President Biden and his administration in their disastrous, tragic handling of the U.S. pullout from Afghanistan: accountability.

Why was it that the president could be so confident in assuring the country only six weeks ago that the U.S. troop withdrawal would be “not at all comparable” to the chaos and desperation it witnessed during the 1975 fall of Saigon?

Or that his secretary of state, Antony Blinken, could tell Congress that the administration was exploring “every possible contingency” to rescue the thousands of Afghans who aided the United States over the past two decades — those who, if left behind, would face Taliban reprisal.

Or that Blinken could further predict: “Whatever happens in Afghanistan, if there is a significant deterioration, in security, that could well happen, we discussed this before, I don’t think it’s going to be something that happens from a Friday to a Monday, so I wouldn’t necessarily equate the departure of our forces in July, August or by early September with some kind of immediate deterioration in the situation.”

All of the things they said couldn’t happen have come to pass, with eerie precision. Whether you agree with Biden’s choice to bring an end to this nation’s 20-year military mission in Afghanistan, it should be a top priority to find out why the president and the top echelon of his foreign-policy team didn’t — or refused to — see what would happen when we departed.

Biden officials suggest that blame for the failure to anticipate the Taliban’s rapid advance rests with the intelligence community, which as recently as June was predicting that it would take six months for the government to collapse after the withdrawal of U.S. troops.

But the accuracy of the timeline is not really the issue. The consequences have always been clear. As my colleague Max Boot has noted, the nonpartisan Afghanistan Study Group, which Congress set up in 2019 to look at policy options and their potential ramifications, used the word “catastrophic” to describe what would happen with an abrupt withdrawal of U.S. troops.

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It is not at all surprising that Biden, who as vice president warned President Barack Obama a decade ago that the military was trying to “jam” him into sending more forces into Afghanistan, would reject the arguments of generals and diplomats that he should go about all of this more cautiously.

During his speech on Monday, the president used Harry S. Truman’s old trope that “the buck stops here,” even as he sought to deflect blame to the Afghans — whose forces Biden touted last month as having “all the tools, training and equipment of any modern military” — and to his predecessor, Donald Trump.

Yes, it’s true that four different presidents share the blame for what has happened, and what hasn’t, in Afghanistan over the past 20 years. But the execution of the U.S. troop withdrawal is something for which Biden alone will be held responsible.

Figuring out the why behind his administration’s missteps is crucial to instilling confidence in its judgment going forward. Otherwise, why should Americans, or the United States’ international allies, accept the president’s assurances that he has “over-the-horizon capability that will allow us to keep our eyes firmly fixed on any direct threats to the United States in the region, and act quickly and decisively if needed”?

It is also hard to hear anything but empty words in Biden’s promise to keep human rights at the center, and not the periphery, of his foreign policy, and to “speak out” for women, girls and others who have much to fear as a Taliban-run Afghanistan tries to force the country back into the 14th century.

Most urgent at the moment is the fate of the Afghans who worked with U.S. forces as translators and in other roles, as well as so-called Priority 2 personnel — development workers, journalists, women’s activists — who shared and invested in the vision of a modern Afghanistan. They and their families are in a desperate situation, as the chaotic scenes from Kabul’s international airport show. Biden’s inadequate contingency planning for them is a historic failure to live up to the United States’ moral obligation.

Biden’s expertise in foreign policy was supposed to be one of his chief selling points as president. “I’ve worked on these issues as long as anyone,” he said Monday, and “I came to understand firsthand what was and was not possible in Afghanistan.” Yet he and his administration’s top officials express surprise at how things have unfolded.

What is at question — now and going forward — is not Biden’s experience, but his judgment.