It will be four years since the U.S. withdrew from Afghanistan on Aug. 30, 2021, ending a nearly 20-year occupation that could serve as a poster child for mission creep.
What began in October 2001 as a narrow intervention to destroy al-Qaeda, the terrorist group that perpetrated the 9/11 attacks, and topple the Taliban government for refusing to hand over al-Qaeda’s leader, Osama bin Laden, morphed into an open-ended nation-building operation that killed 2,334 U.S. military personnel and wounded over 20,000 more.
But the failure of the war to deliver on its maximalist platitudes of bringing peace, democracy, and women’s rights to a nation that rejected them has obscured two of the most important lessons from the conflict and its end: first, the U.S. need not occupy a country indefinitely to prevent terrorism against the U.S. homeland. Second, the United States will severely punish any government that allows terrorist groups to attack U.S. targets from its territory, and the threat of U.S. punishment is a highly credible deterrent against state-sponsored terrorism.
Those two facts should be shouted from the rooftops of the nation’s capital any time members of the foreign policy establishment claim that the U.S. must deploy troops to far-off locales to prevent terrorist “safe havens” from emerging.
In fact, there have been zero terrorist attacks directly linked to Afghanistan against U.S. targets at home or abroad in the four years since the U.S. departed. Zero. The 2025 Bourbon Street attack, which killed 14 people, was perpetrated by a lone-wolf U.S. citizen who was “inspired” by ISIS ideology but acted alone, with no known contacts to the original ISIS or its Afghan affiliate, ISIS-Khorasan (ISIS-K).
That’s despite fevered warnings of worst-case scenarios that would supposedly result if the U.S.-backed Afghan government crumbled in the wake of our military withdrawal. That government did fall, rapidly, and the Taliban regained control as feared. Yet we have not seen a resurgence of jihadist terrorism targeting the United States.
There are two big reasons why. First, effective counterterrorism does not require boots on the ground, so leaving Afghanistan has not hampered U.S. efforts in that security space. The United States is extraordinarily capable of detecting and disrupting international terrorist threats with over-the-horizon intelligence and targeting capabilities.
In the nearly 25 years since 9/11, U.S. counterterrorism capabilities have grown so sophisticated that there are no “safe havens” from U.S. reach, even in a Taliban-led Afghanistan. The U.S. didn’t need troops on the ground to locate and kill al-Qaeda leader Ayman al-Zawahiri in Kabul with a drone strike on his safe house in July 2022, for example.
Nor has a presence been necessary for authorities to foil the handful of plots tenuously linked to ISIS or ISIS-K against the U.S. in the past few years, including the 2024 Election Day plot in Oklahoma and a potential assault on a U.S. Army base in Michigan in 2025. Neither plot was well-advanced, and while the suspects believed they were conspiring with foreign terrorists, it’s not even clear those contacts were real. The would-be assailant in Michigan, a teenager, was actually communicating with undercover F.B.I. agents posing as ISIS members all along.
U.S. and allied intelligence services have also foiled multiple plots in Europe linked to international terrorist groups since the U.S. left Afghanistan and were able to alert Iran and Russia of the looming ISIS-K attacks on those countries in 2024 – warnings that were tragically disregarded by local authorities, resulting in the loss of nearly 250 lives.
Withdrawing troops from Afghanistan has actually made the U.S. less vulnerable to terrorism by depriving local groups of U.S. targets to attack. The last – and only – mass casualty attack ISIS-K perpetrated against the U.S. occurred during the chaotic withdrawal itself, when 13 U.S. troops providing crowd control at the Kabul airport were killed alongside 170 Afghan civilians by a lone suicide bomber.
With U.S. troops gone, hurting the U.S. is much more difficult. In fact, ISIS-K has never managed to strike U.S. targets outside of Afghanistan.
The second reason Afghanistan hasn’t devolved into a launching pad for anti-U.S. terrorism is that the Taliban government knows that the United States will not tolerate it — from Afghanistan or anywhere else. If the 20-year Afghanistan War proved anything, it’s that the threat of massive U.S. retaliation for state-sponsored terrorism is both deadly serious and a powerful deterrent against allowing terrorists to operate freely.
It's ironic that U.S. policymakers worry so much about establishing credibility in marginal situations but can’t recognize overwhelming U.S. credibility where it does exist.
It should be unsurprising, then, that the Taliban have largely upheld their pledge from the 2020 Doha peace deal to never again allow armed groups to menace the U.S. homeland from Afghan territory. That assurance was credible, not because of any trustworthiness or altruism on the Taliban’s part, but because it served the regime’s own interest in political survival. Permitting a repeat of 9/11 would be regime suicide, and since returning to power, the Taliban have fought a protracted campaign to weaken ISIS-K.
Moreover the Taliban has not allowed al-Qaeda to revive itself, despite friendly ties to the group. Al-Qaeda “is all but destroyed” in Afghanistan, according to Bruce Riedel, a former U.S. counterterrorism official, and U.S. intelligence believes the group is unlikely to reconstitute.
Realizing that boots on the ground are unnecessary to disrupt foreign plots and deter state-sponsored terrorism should be enormously consequential for security efforts going forward. It means the U.S. can safely end its anti-ISIS mission in Iraq next month, as planned, and withdraw all 2,500 U.S. troops from the country by the end of 2026.
It also reinforces the wisdom of the ongoing U.S. drawdown from Syria and suggests the U.S. footprint there should be completely removed. And it undercuts any rationale for deploying U.S. forces across more than 10 countries in Africa — or anywhere else — that purported “sanctuaries” could arise.
The U.S. must implement the lessons learned from the Afghanistan withdrawal. Those lessons came at a steep price. Let’s do what we can to not pay it ever again.
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