For others, it was a slow, creeping disillusionment.
But for most of them, watching as the Taliban reclaimed the country in a chaotic scene that unfolded as the American-backed government quickly collapsed evoked a range of emotions and left them questioning the sacrifices.
“I’m 0-2 in foreign wars; I watched the Iraqi army fold like a lawn chair, too,” said Jeff, a former U.S. Marine who did two tours in Iraq and one in Afghanistan and asked that his last name not be used because of his current job. “I thought I was going to be OK with this, but I’m simply not.”
Jeff said he’s had trouble focusing on his daily life for the past week as his TV has been filled with images of the Taliban’s gains and fleeing Afghan civilians.
“I keep going back and forth about how I feel about it: angry, sad, embarrassed,” he said. “As someone whose family business is the military, going back to literally the Revolutionary War, I never wanted to do anything else other than serve. I am completely embarrassed of my country right now.”
The emotions aren't about politics for many of the former soldiers.
“I'm not mad that we're leaving,” said John Rogers, who served with the Army in Afghanistan in 2010 and 2011 as an engineer. “I even voted for [President Joe] Biden because I felt [former President Donald] Trump would have been worse. But Biden wanted to rip the Band-Aid and move on without thinking if the wound is still open. It is, and there will now be a visible and unnecessary scar.”
The American military spent two decades in Afghanistan, much of the time focused on what for many now feels like a futile effort to build up the nation.
Build a base on one tour only to tear it down the next time they were in the country. Defend a key dam from the Taliban for the third time only to hear that the next unit was asked to do the same. Or watch as the Afghan soldiers they worked hard to train would run at first sound of an incoming mortar.
Vets say they knew the country’s longest war would probably not end with a ticker-tape parade. But they didn’t think the collapse would be quite so quick and complete after the U.S. spent 20 years, thousands of American lives and some $2 trillion in the country.
“It seems like a lot of the ‘why’ is being washed away,” said Colin Dewey, a Navy veteran who is still wracked with doubts about his work in Afghanistan helping to select targets to be killed or captured.
This generation of veterans was created on Sept. 11, 2001, when many rushed to recruiting centers to join and serve in what they thought would be a noble war to bring to justice those who supported the terrorists who attacked America. But two decades later, the fall of Kabul feels to many who served like an especially dismal exclamation point.
Still, many veterans like Jeff say they don't regret serving.
“Honest to God, it was the best job I ever had. I wouldn't change it for the world,” he said. “It’s just how it ended.”
While less than 1 percent of the overall American population is in the military, 79 percent of new Army recruits have a family member who served, underscoring the loyalty many feel to the armed services.
Now, some are questioning whether they want that legacy to continue.
Sam Brown’s father and brother both served in Afghanistan, as did he. His wife served in Iraq. In 2008, while leading an Army infantry platoon in Kandahar, Brown's vehicle was struck by an improvised explosive device that left him severely wounded and scarred.
“In today's environment, I would not be encouraging my kids to join the military,” he said, though he and his wife agreed to let their three children decide for themselves. “I would not want my children to be pawns in someone else's political ordeal.”
Brown, who is running for Senate as a Republican in Nevada, like many other veterans said he feels a sense of “betrayal” by political and military leaders who kept insisting over many years and administrations they were just about to turn the corner — only to see it end like this.
“Those people have lost all credibility,” he said. ”We can't just pull out and leave behind this devastating gaping hole.”
'When you start wars'
Many blame war planners and political leaders for caring more about the next election or promotion than the next life lost. And they take umbrage that the news coverage seems at least as focused on the partisan political fallout as the humanitarian disaster.
“We learned nothing from Vietnam,” said Jack Robbins, a former Marine infantry officer who served in Afghanistan in 2006. “The ‘best and brightest’ betrayed the American promise yet again and perhaps converted more to jihad in the last week than [Osama] bin Laden did in a lifetime. Listen to the infantryman.”
Many veterans say their hearts now are breaking for Afghan civilians who will have to live under Taliban rule, and especially for the interpreters and others left behind.
Curtis Grace had suspected for eight years that a day like this would come, since his first deployment as an Army infantryman to Panjwai, the spiritual homeland of the Taliban, when he saw how the Afghan military seemed almost set up to fail without American support.
He and fellow infantryman Luke Coffey, who started a podcast to tell the story of their tiny piece of the sprawling war, have spent the past month trying to encourage fellow veterans to zoom in on their personal experience despite the bleak big picture.
"Your service did matter. Your individual service did matter. We don't make policy," he said. "I hope those stories become the legacy of Afghanistan, not C-17s dropping people on the tarmac."
For the rest of America, it was easy to ignore the wars.
“The chaos we're seeing in real time is a good representation of what the 20 last years looked like, except that America wasn't paying attention,” said former Marine Adam Weinstein. "A lot of what we were doing felt like we were just digging holes in the desert for the sake of digging holes in the desert."
They say veterans shouldn’t be the only ones grappling with the moral and meaning of a war they fought on the Americans' behalf.
“This is the wages of empire. This is the s--- you have to deal with when you start wars,” said Richard Allen Smith, who served with the 82nd Airborne Division in Afghanistan 2007 and 2008. “This, on our conscience, is the price to be paid.”