How does one begin to calculate the cost of the so-called “War on Terror” on Muslims?
Start by counting the dead.
Costs of War Director Stephanie Savell estimates that at least 4.5 to 4.7 million people have died as a consequence of the post-9/11 wars.
More than 940,000 were killed directly by war violence, while an estimated 3.6 to 3.8 million died indirectly as war devastated healthcare systems, economies, water supplies, food security and basic infrastructure.
Savell stresses that the precise mortality figure remains unknowable. What is clearer is that the consequences of war do not end when the bombing stops.
These are not simply numbers belonging to history. They represent a quarter-century in which Afghanistan, Iraq, Pakistan, Syria, Yemen and other overwhelmingly Muslim societies became battlefields in what Washington called the “War on Terror”.
And while the language surrounding that war has changed, much of the legal and military architecture constructed in its aftermath remains.
From 9/11 to a global war
On September 11, 2001, al-Qaeda carried out attacks in the United States that killed nearly 3,000 people.
The murder of civilians was indefensible. Islam provides no authority for massacring innocent people in New York — or anywhere else.
But the response would expand far beyond pursuing those responsible.
Less than a month later, US forces entered Afghanistan after the Taliban government was accused of harbouring Osama bin Laden and al-Qaeda. What began as an operation against those responsible for 9/11 became a 20-year war.
Then came Iraq.In March 2003, the United States and its allies invaded Iraq after Saddam Hussein’s government was accused of possessing weapons of mass destruction.
The stockpiles used to justify the invasion were never found. The Iraq Survey Group later assessed that Iraq had clandestinely destroyed almost all of its biological weapons and long-range missiles in 1991.
Iraq was also not responsible for the September 11 attacks. The official 9/11 Commission found no credible evidence that Saddam Hussein’s government participated in the attacks or developed a collaborative relationship with al-Qaeda in carrying them out.
Yet Iraq would become one of the countries to pay the heaviest price.
Research by Costs of War co-founder Neta Crawford estimates that between 550,000 and 580,000 people were killed in Iraq and Syria between 2003 and 2023, while potentially far more died indirectly from preventable disease, destroyed infrastructure, displacement and prolonged instability.
When does a war end?
The phrase “War on Terror” is heard less frequently today.
But much of the system created to prosecute it survives.
After 9/11, the US Congress passed the 2001 Authorization for Use of Military Force (AUMF), giving the president authority to use force against those responsible for the attacks and those who harboured them.
What followed was a dramatic expansion in how that authority was interpreted.
Savell found that successive US administrations cited the 2001 AUMF to justify counterterrorism operations in at least 22 countries, including airstrikes, combat operations, detention and support for partner militaries.
The concept of “associated forces” became particularly significant.
The original authorisation targeted those responsible for September 11. Over time, however, successive administrations interpreted it to encompass organisations deemed associated with al-Qaeda or the Taliban — including groups that did not even exist when Congress passed the law in 2001.
Twenty-five years later, the 2001 AUMF remains in force.
The US government’s 2026 report on its use of military force states that the formal scope of the authorisation underwent “no change” during 2025 and confirms that US forces continued operating against ISIS and al-Qaeda in Iraq and Syria under the 2001 AUMF.
That does not mean every American military operation today can simply be classified as part of the War on Terror.
Military action in Iran, Yemen and other theatres has also relied on separate presidential authorities. The same White House report says Article II powers were used for military force in countries and regions including Iran, Iraq, Somalia, Syria and Yemen during 2025.
But the broader machinery constructed after 9/11 remains: permanent counterterrorism operations, overseas military deployments, drone warfare, expansive executive powers and a security framework capable of continually incorporating new adversaries.
That is why the term “War on Terror” itself deserves scrutiny.
Terrorism is a tactic. It is not a state that can surrender, sign a peace treaty and formally bring a conventional war to an end.
A war against something defined so broadly risks having no clear endpoint at all.
Muslim societies bore the heaviest burden
The geography of the deaths cannot be ignored.
Costs of War estimates that more than 940,000 people were killed directly in post-9/11 war violence, including more than 432,000 civilians. More than 38 million people have also been displaced across countries affected by these conflicts.
The estimate of 4.5 to 4.7 million deaths should not, however, be presented as 4.7 million Muslim deaths. Researchers did not classify every victim according to religion, and Christians, Yazidis and other communities also suffered terribly.
But the overwhelming burden of these wars fell across Muslim-majority societies.
Islam rejects collective guilt with unmistakable clarity:
“No bearer of burdens will bear the burden of another.” [Qur’an 6:164]
Nineteen hijackers committed the crime of September 11. Afghan children did not. Iraqi families did not. Yemeni villagers did not.
No Muslim civilian inherits the guilt of al-Qaeda merely because they share a religion with its members.
The same moral principle applies to al-Qaeda, ISIS and any armed group when they murder civilians. Islamic ethics cannot change according to whose weapon causes the death.
“Whoever kills a soul … it is as if he had slain mankind entirely.” [Qur’an 5:32]
The deaths that continue after the bombs stop
Perhaps one of the most disturbing findings in Savell’s research is that the majority of the estimated deaths were not caused directly by bullets, bombs or airstrikes.
War destroys the conditions necessary for people to remain alive.
Hospitals lose medicines. Water systems collapse. Families lose incomes. Food becomes scarce. Disease spreads through displaced communities. Children are often among the most vulnerable.
Savell found that more than 7.6 million children under the age of five in post-9/11 war zones were suffering from acute malnutrition as of 2023.
Those conditions help explain the estimated 3.6 to 3.8 million indirect deaths linked to the wars.
It is therefore no longer enough to ask how many people died during the so-called War on Terror.
The deeper question is how many people continue to live — and die — inside its consequences.
Twenty-five years after 9/11, there is no neat ending to commemorate.
The principal legal authority created in its immediate aftermath survives. The global counterterrorism infrastructure survives. And across Muslim-majority societies scarred by invasion, occupation, bombing, displacement and instability, so do the wounds.
The dead are still being counted.
