The horrors of September 11, 2001, unfolded in just under 102 minutes. On that day, 2,996 people died in the worst terrorist attack in modern history.
What followed was 19 years, 10 months, three weeks and two days of war in Afghanistan, with the Department of Defense counting at least 2,325 American military deaths. No one knows exactly how many civilians were killed.
On September 11, 2021, President Joe Biden will try to draw a line under those twin tragedies, paying his respects at the three sites, whose fiery suffering set alight America's longest war.
On Friday, the president released a video honoring those killed or injured in the attacks, their families, and those who worked to rescue survivors. And he called for national unity.
The Global War on Terror, as it was called, stretched well beyond the small central Asian country of Afghanistan — reaching into Iraq and other corners of the globe as distant as Africa. In Iraq, the conflict killed nearly 4,500 U. S. service members and hundreds of thousands of civilians.
Since the controversial decision to withdraw all troops from Afghanistan by the end of August, the Biden administration has made decisive moves to put the last 20 years behind it, by declassifying a trove of documents that may shed light on the events of September 11, and by maintaining a studied distance from the hardline theocratic Taliban government that seized power in Afghanistan as Americans withdrew.
On Saturday, Biden will visit all three sites that lit the spark: New York City, where at 8:46 on that sunny September morning, American Airlines Flight 11 crashed into the north tower of the World Trade Center — and where, 17 minutes later, United Airlines Flight 175 hit the south tower.
He will also visit the Pentagon, where American Airlines Flight 77 crashed 34 minutes later. And separately, he and Vice President Kamala Harris will pay their respects at a lonely field in Shanksville, Pennsylvania, the final resting place of United Airlines Flight 93.
It is a scripted, almost cinematic close to the past 20 years, said history professor Jeremi Suri of the University of Texas at Austin.
"The president is drawing a line under the last 20 years," he told VOA. "And he's acting as a historian and saying we've ended an era, just like the end of the World War II era, and it's now time to make new decisions in the ways in which Harry Truman made new decisions after the World War II era."
Suri, whose books explore the office of the presidency and U.S. foreign policy, said historians see some logic in how the president is framing this moment.
"But we will also see, as we always do, that one era does not end when a new era begins," he said. "I think we are in a different moment after the 2020 election, and we are in a different moment with the rise of China. But many of the issues from 20 years ago, they still don't have neat chapter endings in the way that we make them look like they do in our books."
Deputy national security adviser Elizabeth Sherwood-Randall says what matters, as the world rounds two decades since 9/11, is that there hasn't been another major terrorist attack.
"Twenty years on, our challenge is different," she said, speaking this week to the Atlantic Council, a global affairs research group in Washington. "We have learned since 9/11 how to protect Americans from terrorism. It isn't fail-safe, and terrible things still happen. But through a combination of actions abroad and at home, we have thus far been able to disrupt and prevent another 9/11-style attack."
But Vanderbilt University historian Thomas Schwartz predicts fallout beyond Saturday's era-ending commemorations.
"I'm probably more critical on this because I don't think that this is something you can actually do," he said. "I think the enemy in a sense has a vote, and they can decide that even if we want to call it off after 20 years, they may not. And in that sense, I think the words of President Biden — and the deeds — of a fixed time for withdrawal from Afghanistan were a mistake and were an error in judgment that I think could affect the United States over the coming years."
The president is likely to speak publicly on Saturday, but "words are not going to make a difference at this point," said Norman Ornstein, a senior fellow at the American Enterprise Institute, a conservative public policy research group in Washington.
"Obviously, he has to give a carefully crafted speech on Saturday, I think in part saying that we have managed through several administrations to avoid another 9/11," Ornstein said. "We managed to capture and kill the man who was behind it, Osama bin Laden, that it's not over yet, and that we made a lot of mistakes along the way. And we're going to try to avoid making mistakes of that sort in the future."
Lebanon in 1983
But he cautions that Americans should look to history to see how this will play out — not to 2001, but to 1983, when President Ronald Reagan decided to withdraw American forces from Lebanon months after a bombing killed 241 U.S. service members. This, Ornstein said, is the fundamental difference between the America of today and the America of past decades.
"We did not have calls for Ronald Reagan to resign, or moves to impeach him," he said, contrasting the situation in 1983 with Republican lawmakers who have harshly criticized the U.S. evacuation from Afghanistan.
"We didn't have this breakdown along partisan lines, and it's a measure, in the not quite 40 years since then, of how much our politics have changed, that everything goes through a kind of tribal lens," he said. "And that is a disturbing element here that actually is at least as unsettling in terms of where the country goes in the future as some of these other threats that we face."
Americans have continued to broadly back the president's decision to withdraw from Afghanistan in recent public opinion polls, but they have also criticized Biden over how his administration handled the evacuation. That is partly responsible for new polls indicating a 43% approval rating, the lowest of his presidency.