Torture became “enhanced interrogation”. Suspects were seized and removed across borders through “extraordinary rendition”. Detainees held at Guantanamo Bay were designated “enemy combatants”, while deadly attacks were described as “surgical” or “targeted” strikes.

In the years after the September 11 attacks on New York City’s World Trade Center, a whole new vocabulary of war, laced with the language of bureaucracy and precision, moved into the political mainstream in the United States.

At its centre was a phrase broad enough to encompass almost everything that followed: the “war on terror”.

That phrase came to define an era in which the US illegally invaded Afghanistan and Iraq, established the notorious Guantanamo Bay holding centre for “terrorists” and dramatically expanded its surveillance and national security powers at home. And it was all facilitated, experts say, by a new lexicon, one that sanitised violence, and erased the humanity of its targets.

Twenty-five years later, the phrase “war on terror” is now heard far less frequently from the White House. But many of the themes and ideas it helped to embed remain deeply rooted in US politics.

“I think we can see the legacy of the war on terror everywhere in US politics today,” Leonie Jackson, a senior international relations lecturer at Northumbria University in the United Kingdom, told Al Jazeera. “In fact, I would argue that we are still very much inside the logic of this ‘war’.”

A ‘war’ without front lines

Nine days after the attacks on New York and Washington, DC in 2001, then-US President George W Bush addressed a joint session of Congress. “Our war on terror begins with al-Qaeda, but it does not end there … It will not end until every terrorist group of global reach has been found, stopped and defeated,” he declared.

Congress had already passed the Authorisation for Use of Military Force, signed by Bush on September 18. The authorisation gave the president broad authority to use force against those he determined had planned, authorised, committed or aided the September 11 attacks, or anyone who had harboured those responsible.

But unlike a conventional war, this was not a war against a specific group or country.

“Terrorism is not a state, a territory or even a specific organisation. It is a tactic,” Christopher Baker-Beall of Bournemouth University told Al Jazeera.

“Declaring a ‘war on terror’, therefore, created a conflict without an obvious geographical boundary or clearly defined enemy and therefore, importantly, no natural endpoint.”

Later that year, Bush laid down a stark challenge for the international community: “Either you are with us, or you are with the terrorists.” Bush also frequently used the term “evil”.

Harmonie Toros, professor of politics and international relations at the University of Reading in the UK, told Al Jazeera that this “language is used to sanitise actions taken by the US – actions that could be seen as not okay for a normal, functioning democracy to undertake”.

At the same time, she said, it represented “a strong discursive effort to demonise” the enemy. Fear, anger and the desire to respond, Toros said, “come together and create this ‘war on terror’”.

The result was a narrative that divided the world not only between allies and enemies, but between notions of “good” and “evil”.

In his paper, 9/11, the Crisis of Meaning, and Disinformation in the 21st Century, Jason Thomas wrote that this stems from colonial ideas of civilisation and barbarism, and the US had constructed a narrative that “asserted the … ‘civilised/barbarian’ as a fundamental axis in world politics”.

When torture became ‘enhanced interrogation’

The US invaded Afghanistan less than a month after the events of September 11, 2001. Then, in March 2003, a US-led coalition invaded Iraq based on repeated claims by the Bush administration that Iraqi leader Saddam Hussein possessed weapons of mass destruction that could threaten the US and its allies. In the end, the stockpiles Washington said it was certain existed were never found, but by that time it was too late.

The “war on terror” quickly expanded into a sprawling network of global military operations and covert operations.

Nearly 780 people would eventually pass through the US military prison at Guantanamo Bay. All but a handful have since been freed without ever being charged with a crime, but some had by then languished in detention without charges for two decades.

When the British-American human rights lawyer Clive Stafford Smith first arrived at Guantanamo to render legal aid to detainees there shortly after it opened – he was among the first lawyers to be granted access – he said he saw boys as young as 14 being held. “The Guantanamo detention camp was born a sorry lie and it remains one,” Stafford Smith wrote for Al Jazeera in 2022.

Besides Guantanamo, the CIA operated secret detention facilities, or “black sites”, overseas while the abuse and torture of prisoners by US forces at Abu Ghraib prison in Iraq became one of the defining scandals of the war.

Oiling the wheels for those practices was a language that often appeared deliberately clinical. Torture and abusive interrogation methods including the notorious practice of waterboarding, prolonged sleep deprivation and stress positions were described as “enhanced interrogation techniques”. The covert transfer of detainees outside ordinary judicial processes became “extraordinary rendition”.

“What is striking about many of these terms is their bureaucratic or technical character,” Baker-Beall said. The effect was to create “moral and political distance” which “can sanitise acts of extraordinary violence and turn them into something that sounds like an ordinary instrument of government policy”.

In a series of legal memoranda which became known as the “Torture Memos”, lawyers in the Bush administration constructed an extraordinarily narrow interpretation of what constituted torture as the CIA sought legal authority to use increasingly brutal and coercive interrogation techniques.

Jackson said euphemistic language helped cloak such practices in “a veneer of legality”, allowing leaders to violate international legal protections, while maintaining the image of the US as the “good guys”.

Tahir Abbas, professor of criminology and global justice at Aston University in the UK, told Al Jazeera “this language also desensitised ordinary members of the public, rendering them increasingly numb to the deeply dehumanising and depersonalised ways in which death and destruction were discussed”.

“Often in relation to innocent victims,” he added.

Suspicion and the surveillance state

Forty-five days after September 11, Bush signed the Patriot Act, vastly expanding the surveillance apparatus of the US government and making it easier for intelligence and law enforcement agencies to share personal information.

The post-9/11 security architecture also transformed the way immigration, borders and domestic policing were understood. The Department of Homeland Security was established in 2002, bringing numerous agencies responsible for borders, immigration, transport and security under a single national security structure.

Security policy became increasingly concerned not simply with what somebody had done, but with what they might do.

“The key political shift went from responding to actual threats towards governing possible future threats,” Baker-Beall said. “Once that happens, the potential scope of security policy becomes much wider.”

That logic created political space for intelligence gathering, detention, border controls and executive power. Governments across Europe also introduced sweeping counterterrorism laws and expanded surveillance, while Muslim communities increasingly found themselves on the receiving end.

Abbas described the result as a “boomerang effect”, in which citizenship stripping, securitisation and surveillance became normalised in the lives of Muslims.

The language of the war on terror, he said, helped build a wider politics of “othering”, in which entire communities could be cast as sources of danger – making mere suspicion itself a justification for surveillance, detention and other forms of state control, even when individuals had done nothing wrong.

What the ‘war on terror’ left behind

By the time Barack Obama became US president in 2009, the new terminology had begun to change. On 23 May 2013, Obama announced that the “war on terrorism” was over.

But the institutions built in the wake of September 11 did not disappear with it. US Immigration and Customs Enforcement, or ICE, was created as part of the Department of Homeland Security, its enduring legacy being increasingly frequent images of ICE agents patrolling streets in balaclavas arresting people of colour and assaulting protesters since Donald Trump began his second term as US president last year.

Far from being shut down, Guantanamo Bay – itself perhaps the most recognisable physical symbol of the post-9/11 suspension of ordinary legal norms – has been used by the Trump administration to detain migrants.

The war on terror, therefore, left behind a legacy of constructing threatening communities: “a practice of villainising a specific group of people”, Toros said.

“It can be gangs or a specific immigrant group, or even gender or gender identity. Post-9/11 and all the war on terror discourse allowed people to become more skilled when the intent is to villainise a community.”

And its legacy expands into US foreign policy, with Trump ordering the executive branch in 2025 to use the name “Department of War” as a secondary title for the Department of Defense, saying that the name better conveyed America’s willingness not simply to defend itself but to fight and win wars.

And those ideas have played out on Trump’s watch. The US is once again at war in the Middle East, with Trump claiming that military action against Iran was necessary to prevent it from developing a nuclear weapon – a justification that has drawn comparisons with the claims about weapons of mass destruction used in the run-up to the invasion of Iraq in 2003.

The Trump administration has also drawn on parts of the post-9/11 lexicon while developing a vocabulary all of its own. Military action has again been framed through the language of “pre-emptive” and “precision” strikes, while Iran has repeatedly been described as a “terror regime” and the “world’s leading state sponsor of terrorism”.

“It is not simply a continuation of the ‘war on terror’ and the circumstances are very different,” Jackson said. “But the same pre-emptive security logic is familiar.”

“What is striking is the continuing power of the same political argument: We cannot afford to wait for the threat to materialise, so action has to be taken now.”

She added that “the legacy of the war on terror everywhere in US politics today”.

“We may have moved away from the language of the war on terror, but its effects remain deeply ingrained in US society.”