The bloody coda to a tortured 20 years -- the loss of at least 170 people in addition to 13 US service members in the blast -- exemplified the human tragedy and ultimate futility of a conflict that failed in its core purpose: purging Afghan soil of terrorism. In a cruel irony, the latest Americans to die perished in an attack conceived in the very same land as the al Qaeda assault on September 11, 2001, that triggered the war they were trying to leave.
The atrocity rocked the final stages of the frantic US evacuation of as many as 1,000 Americans who may still be in the country, as well as thousands of Afghans who helped US forces and officials and fear Taliban executions if they are left behind.
It also shone a harsh light on President Joe Biden's decision-making and the chaotic nature of the US withdrawal that left American troops and civilians so vulnerable, in the confusing, chaotic days after the Taliban seized Kabul.
The most alarming realization in the aftermath of the carnage was that there may be more to come before the deadline for the US to leave for good on Tuesday. Biden and Vice President Kamala Harris were warned by their national security team on Friday "another terror attack in Kabul is likely," according to White House press secretary Jen Psaki.
Gen. Kenneth "Frank" McKenzie, who heads US Central Command, warned on Thursday that new threats from ISIS-K, possibly involving rockets or vehicle borne suicide bombs could be imminent. That means that the coming days will be among the most tense and dangerous of the entire war for US troops. And the awful possibility remains that the country's last victim of the first post-9/11 war is yet to die.
At a time of national tragedy, nations turn to their leaders. Biden, who spent much of the day in the White House Situation Room, emerged in the late afternoon on Thursday for a televised speech. Torn between grief and resolve, he vowed vengeance. "We will not forgive. We will not forget. We will hunt you down and make you pay," the President told the terrorists in remarks that mostly seemed aimed at projecting strength to Americans at home.
"We will respond with force and precision at our time, at the place we choose, and the moment of our choosing," the President said. Biden's withdrawal marks the symbolic reversal of the US arrival in Afghanistan launched after 9/11 and the strategy of putting troops on the ground in foreign states to fight terrorism.
But ironically, his pledge of revenge mirrored one made by ex-President George W. Bush days after the world's worst terrorist attacks. "This conflict was begun on the timing and terms of others; it will end in a way and at an hour of our choosing," Bush said at a prayer service at Washington National Cathedral. The similarity reflected the truth that American presidents -- for all their nation's power now somewhat drained by an exhausting two decades-long war -- can be singularly challenged by terrorism, an asymmetric threat that cannot defeat the United States but can wound it and threaten to drag it into perpetual conflict.
Some things in Biden's speech don't add up
Biden's address on Thursday was punctuated by several contradictions.
First, his vow to "complete the mission" of extracting from the country all remaining Americans and Afghans who helped US forces appears impossible, given that he is not planning to extend the deadline for withdrawal past Tuesday. His talk of carrying on trying to get America's friends out after US troops leave seemed to confirm he understands the impossibility of wrapping up that mission in four days. But getting Afghans out of the country without having US forces there will be even harder.
Secondly, Biden's efforts to strike back hard at ISIS-K -- the first real test of what he calls "over the horizon" capabilities to ensure that Afghanistan does not again become a terror haven that could threaten US security -- means US operations in the country are not ending, but are changing.
"U.S. military forces conducted an over-the-horizon counterterrorism operation today against an ISIS-K planner," Central Command spokesman Capt. Bill Urban said in a statement Friday evening. "The unmanned airstrike occurred in the Nangarhar Province of Afghanistan. Initial indications are that we killed the target. We know of no civilian casualties."
If nothing else, Thursday's airport attack exemplified the dilemma Biden faced when he was asked by allies to extend the deadline. By leaving, he may be unable to bring every American and thousands of allied Afghans out of the Taliban's clutches. But staying would expose US troops to even graver danger.
The bombing also laid bare the extreme weakness of the US position in Afghanistan. After fighting the Taliban for 20 years, American forces are now reliant on the same insurgents with no experience in providing security to prevent terrorist attackers reaching the Kabul airport -- an arrangement that failed disastrously before the bombings. But the President insisted it was not a mistake to rely on US enemies for help.
"It's not what you would call a tightly commanded regimented operation like the US military is, but they are acting in their interests," he told reporters after his speech.
The Pentagon said Friday there was only one explosion at the Abbey gate at the airport, after saying in initial statements Thursday that there was a second explosion outside a hotel near the airport gate.
But that attack was another knock on the administration's planning and management of an evacuation that ended up depending on an airport in the middle of an impossible-to-secure urban area in one of the most lawless cities in one of the world's most failed states. Already, the tragedy is raising scrutiny of another decision, to walk out of the vast former US base at Bagram airfield, and critics now wonder if there were ever sufficient troops in the country to effect a safe, efficient withdrawal.
Biden's leadership questioned
During a chaotic 10 days, Biden's defenders have accused those who have criticized his performance of trying to saddle him with the failures of three previous presidents and disastrous decisions that lost the war years ago. Tragically, their talking point -- that no US troops had died in the effort -- is now moot and always showed little appreciation of the hugely perilous environment inside Afghanistan.
It is true that many of the ex-official and military pundits on television faulting Biden's leadership are the exact people whose strategic decisions backfired when they worked for various administrations. And Biden was dealt a tough hand by ex-President Donald Trump, who had negotiated an even earlier exit from Afghanistan, and whose sidelining of the government in Kabul helped precipitate the collapse of the Afghan state.
It is also ironic that Biden, who was all along one of the most skeptical Washington leaders of the US nation building project in Afghanistan, should end up carrying the can for the consequences of the eventual US departure.
But Biden also ran for office in 2020 on a platform of competence and he styled himself as a foreign policy expert. It is hard to look at the debacle of recent days and see those qualities at work. Most of Biden's televised predictions -- that the Taliban wouldn't suddenly overtake Kabul and there would not be a Saigon-style exit for the US -- were wrong. And he now seems vulnerable to Republican charges of weakness and stumbling leadership that may not be completely fair given the impossibility of his choices in Afghanistan but represent a real political danger ahead of the midterm elections.
Still, a time of grief and emotion is never a good time for political prognostications, and it is possible the American people will process the imagery of defeat and horror in Kabul as validation for his decision to finally get all US troops home. While hawks lambast him for retreating from the war, there is a historical precedent that suggests he may be on firmer political ground. President Ronald Reagan withdrew US troops from Lebanon in early 1984, months after 241 US personnel were killed in a bombing of a US Marine barracks. He won a landslide reelection victory later that year.
"Joe Biden has a very intuitive sense of the American people. He understands that there is a great deal of American support for Republicans as well as Democrats for reducing America's involvement in the world," Timothy Naftali, a presidential historian at New York University, told CNN's Erin Burnett.
"One of the things he is banking on is a short period of chaos will be accepted by the American people as a down payment on a future more sustainable American position in the world."
To this point, Biden was asked at the White House if, after the horror of Thursday, he regretted his decision to follow through on Trump's withdrawal.
"Our interest in going was to prevent al Qaeda from reemerging, first to get Osama bin Laden, wipe out al Qaeda in Afghanistan, prevent that from happening again," Biden said. "Ladies and gentleman, it was time to end a 20-year war."
Naftali, however, warned that a large part of Biden's legacy would be dictated by whether terrorists with the power to attack the US will find a new haven in the anarchical atmosphere of Taliban-run Afghanistan.
And as Thursday showed, presidents for all their power, are often hostage to horrific events beyond their control.
This story has been updated with US Central Command's corrected spelling of the Nangarhar Province and additional developments Friday.
CLARIFICATION: An earlier version of this story misstated that the 13 American service members were counted among the 170 people killed.
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