Most Millennials remember 9/11. The sadness that a tragedy of such proportion had struck at the heart of the country’s flagship city, the fear of further attacks, and the anger towards those who had carried them out were felt by American youth at the time.

But 25 years on, those emotions have shifted into a very different set of feelings that are focused more on the country’s response to being attacked and less on the tragedy itself. Compared with older generations, Millennials (those born between 1981 and 1996) have grown increasingly skeptical of the use of force that was justified as necessary to respond to this great tragedy. As Millennials step into roles of power in the U.S. political system, that viewpoint is likely to change the country’s foreign policy in ways both big and small. 

The George W. Bush administration was successful in using the attacks on Sept. 11^th, 2001, as justification to use military force against Afghanistan, and two years later, Iraq. Congress and the American public initially backed both with large majorities. In 2001, 88% of Americans approved of the invasion of Afghanistan, according to Gallup, and in 2002, in the leadup to the decision to invade Iraq, the Pew Research Center reported that 73% supported use of force against the country. These numbers were not isolated to older generations. A November 2001 survey of college students conducted by Harvard’s Institute of Politics reported that 79% supported air strikes in Afghanistan. Polling later in 2002 by Pew found that Americans aged 18-29 were more likely to support military action against Iraq than any other generation.

While the wars in Afghanistan and Iraq were different in myriad ways, they would come to be seen as failures linked together first and foremost by the Bush administration’s justifications that force was needed as a response to 9/11. The ties between the 9/11 attacks and the war in Afghanistan were clear at first, given the campaign was primarily a hunt for Osama bin Laden. But that reasoning became increasingly vague as the war continued for more than a decade after he was killed by U.S. forces in Pakistan in 2011. By the time of U.S. withdrawal from Afghanistan in 2021, the war had been going on for most Millennials’ lives and resulted in the death of tens of thousands and upwards of $2 trillion in U.S. spending.

Tying 9/11 to the invasion of Iraq was far more cynical. As Bruce Reidel, who served as staff on the National Security Council in 2001, wrote, “Despite the intelligence community’s unequivocal conclusion that Iraq had nothing to do with either 9/11 or al-Qaeda, the administration let Americans believe the contrary.” It did not take long before Millennials abandoned their support for the war, which was considered a significant reason for the election of the presidential candidate most critical of the war, Barack Obama, in 2008.

The perception among Millennials that the two wars were futile blended with questions about why the United States was fighting these conflicts in places that appeared disconnected to American interests. This had a lasting effect. According to recent surveys from the Chicago Council on Global Affairs, Millennials are far more skeptical than older generations about the use of force and the use of long-term military bases abroad. By 2012, Millennials were the only cohort in which a majority were worried that the United States military would “go too far” in its campaign against ISIS in Iraq and Syria. And the Millennial cohort remains more pessimistic about the prospects for use of force in places like Iran than other generations.

How the United States used its power under the auspices of countering terrorism went beyond influencing Millennials’ views of war — it led to generational skepticism about the United States being a leader in the world and acting as a force for good. The Chicago Council survey found that most Millennials believe the United States is no greater than other countries, compared with majorities in older generations holding the view that the United States is the greatest country in the world.

For Millennials, 9/11 has been transformed in popular memory from a tragedy that unified the country in grief into the starting point for the expensive and failed Global War on Terror, attacks on civil liberties, and even broader national decline. Instead of sparking heightened patriotism, 9/11 instead evokes memes and conspiracy theories. This phenomenon has in turn led to accusations from older establishment figures that Millennial politicians underplay the horrors of the attacks. These types of accusations have become especially pronounced as people from communities who faced increase suspicion and surveillance after September 11, namely Muslim Americans, enter politics.

As Millennials come into leadership roles, the memory of 9/11 will cast a far different shadow than the attacks did on prior generations. On both the left and right, there is increased skepticism about the size of the military and its role in U.S. foreign policy, as well as broader challenges to the previously dominant view of U.S. primacy. This skepticism is being passed down, as the younger Gen-Z are even more disagreeable to the idea of militaristic foreign policy than their predecessors. U.S. foreign policy will be shaped for decades to come by what is viewed by the majority of potential future leaders as a cynical use of the 9/11 attacks for unjust and failed wars.