People aged under 20 have never known a world before the September 11, 2001 attacks and America's "war on terror".
For them, the United States has always been at war in Afghanistan.
President Joe Biden's decision to unconditionally draw a line under US involvement in a country which has historically been a quagmire for foreign invaders has been a long time coming.
His predecessor Donald Trump had eyed May 1 as a date for withdrawal while peace talks continued and the Taliban gobbled more territory. According to the UN, more than 1700 civilians have been killed or wounded in attacks so far this year, up 23 per cent from the same period last year.
Biden said: "There are many who loudly insist that diplomacy cannot succeed without a robust US military presence to stand as leverage. We gave that argument a decade. It's never proved effective. Our diplomacy does not hinge on having boots in harm's way."
A war that was originally about revenge for the terror attack and destroying al-Qaeda, became a seemingly endless and costly attempt to prop up a government and its military under siege from the Taliban.
The US tried a troop surge to squash the Taliban without success and soldier numbers peaked at 100,000. There were continual reasons found not to leave. Afghanistan couldn't become a base again for extremists bent on attacking the US. The "conditions on the ground" had to be right to get out. The Afghan armed forces had to be trained.
The US pullout of its remaining 2500 troops means Nato is withdrawing about 7000 soldiers and Australia its final 80.
New Zealand announced in February it would withdraw its last six defence personnel by May. The conflict cost 10 Kiwi lives, and 3500 New Zealand troops and officials were deployed there over the years.
Biden's withdrawal, which would be regardless of whether the Afghan regime is in danger of collapsing or not, appears to be primarily about domestic considerations.
A Pew Research Centre poll in 2019 showed nearly 60 per cent of American respondents believed the war wasn't worth fighting.
But it's also about convincing Americans that the key task for the superpower is to avoid gradually crumbling from within than being distracted by conflicts without, and that its influence has to be used differently.
Timing the US pullout for the 20th anniversary of the al-Qaeda terror strike is meant to put a full stop on the militaristic, security-focused past two decades.
Biden has said he wants to focus on improving America's competitiveness and social stability in other ways. His interest is in boosting infrastructure, research and investment, technology, supply chains, tacking economic and racial inequalities.
That means acknowledging and attempting to improve its deep-rooted problems to deal with China and Russia from a position of structural strength.
Clearly there are other strategic and security problems to focus on.
Conflict is also waged with malware, and space is its next frontier with hypersonic weapons. On Earth, Russian forces are menacing Ukraine, Chinese warplanes have been intruding in Taiwan's airspace. Myanmar is in a bad way. It's unclear whether the nuclear pact with Iran can be revived.
Afghanistan has essentially been two wars.
There's the one the outside world has focused on, which is how it relates to US and allies' objectives. Then there's the war as it has been experienced by the country and its people.
In two decades, 2200 US troops have been killed and 20,000 wounded. It has cost more than US$1 trillion. The deaths of Afghan civilians have been in the tens of thousands.
For Afghanistan, this is a step into the unknown.
The regime has been trying to work out an effective ceasefire with the Taliban, which hasn't committed to power-sharing. Further talks are due to be held soon in Turkey.
The pullout could spur the sides towards a deal or herald a vicious scrap between government forces, the Taliban, warlords and Isis.
Political and military chaos likely looms and possibly a return to oppressive Taliban rule. Women live under tight restrictions in Taliban-controlled areas.
The world may no longer care, but the endless war isn't going anywhere.