There are events that happen within history, and there are events that change its direction. The attacks of 11 September 2001 unquestionably belonged to the latter.
Twenty-five years ago, Al-Qaeda's attacks on New York and Washington killed almost 3,000 people, traumatised the US and produced images that became instantly seared into global consciousness.
But 9/11 was more than an atrocity. It altered the course of an era.
Barely a decade after the collapse of the Soviet Union, the US stood as the world's sole superpower and liberal democracy appeared to have no serious ideological rival. Francis Fukuyama's famous declaration of the "end of history" captured the extraordinary confidence of the age.
Liberal democracy, globalisation and an international system supposedly governed by universal rules appeared not merely ascendant, but inevitable.
Then the planes hit.
A quarter of a century later, that world seems almost unrecognisable. Liberal democracy is in retreat, the far right is ascendant across much of the West, most notably in the US, Russia is waging a war of territorial conquest in Europe, and the international rules supposedly restraining state power appear increasingly conditional.
This week provided another remarkable marker of how far we have travelled. The far-right Alternative for Germany (AfD) won 43.8% of the vote in Saxony-Anhalt, its greatest electoral result to date, bringing a party once considered beyond the limits of respectable German politics tantalisingly close to governing a German state.
None of this can be solely blamed on 9/11. But nor can the world of 2026 be understood without examining what the US and its allies did in response to it.
The Global War on Terror (GWOT) transformed more than US foreign policy. It changed the relationship between security and liberty and helped normalise the idea that extraordinary threats demanded extraordinary powers.
The Patriot Act vastly expanded surveillance. Guantanamo Bay became a legal black hole in which alleged "enemy combatants" could be detained indefinitely without charge. The CIA abducted suspects and transferred them through an extraordinary rendition programme to states where torture was routine. The invasion of Iraq showed that even the world's leading liberal democracy was willing to bypass the international order it claimed to defend.
The Bush administration was not pursuing an explicitly illiberal project. Quite the opposite: it believed US power could protect and ultimately spread liberal democracy.
But it pursued liberal ends using profoundly illiberal means.
That distinction matters. Donald Trump is not simply George W. Bush with the mask removed, nor did the Patriot Act somehow inevitably produce the AfD. But the GWOT created a political world in which exceptional measures became increasingly normal and showed how easily restraints on state power could be discarded once "security" was invoked.
I have previously called what followed the "procession of illiberalism": ideas and machinery created for the War on Terror being taken up and repurposed by movements with very different, explicitly illiberal goals.
The Western front
Orban's Hungary became perhaps the clearest European example.
During his 16 years in power, Orban openly set about building what he called an "illiberal state". His governments expanded Hungary's counterterrorism apparatus while increasingly depicting Muslim migrants as an existential threat to Hungary and Christian Europe.
The terrorist became the extremist; the extremist became the Muslim migrant; those helping migrants became accomplices; and eventually multiculturalism, LGBT rights, liberal civil society and "globalism" itself were portrayed as threats to the survival of the nation.
Orban may have lost power this year, but the politics he helped pioneer travelled far beyond Hungary.
The AfD's victory in Saxony-Anhalt cannot be reduced to this history. Economic stagnation, anger at Germany's established parties and the particular history of eastern Germany all matter.
But today's European far right operates on political terrain profoundly shaped by the post-9/11 era. Borders become front lines and migration becomes invasion. Muslims are treated as a civilisational danger, while multicultural liberal democracy itself is presented as something weakening the nation from within.
In Trump's US, the process has become almost absurdly literal.
Guantanamo, perhaps the ultimate physical symbol of the GWOT's suspension of normal rules, has been repurposed for the detention of migrants. Immigration and Customs Enforcement (ICE), itself created by the Bush administration during the War on Terror, has become the frontline institution of Trump's mass-deportation programme.
The machinery and language built to confront foreign terrorists have turned inwards.
The targets have changed, but the logic is familiar. Identify an existential enemy, strip away normal protections and invoke security to justify extraordinary state power.
The War on Terror never left the Middle East
If the GWOT has turned inward in the West, in the Middle East its original logic never really disappeared.
Israel's genocidal war on Gaza made this explicit. Israeli leaders repeatedly invoked 9/11 and presented the war as part of the same civilisational struggle against terrorism. Benjamin Netanyahu described 7 October as Israel's own 9/11 and compared Israeli military action beyond its borders to what the US did after the attacks.
The comparison is revealing.
Once again, an appalling terrorist attack became the justification for an overriding security imperative. Once again, exceptional violence was presented as necessary because the threat was existential. And once again, international law was treated as secondary to the state's claimed need to destroy its enemy.
The results in Gaza have been catastrophic - the enclave devastated, tens of thousands of Palestinians killed and most of its population displaced, while the US supplied the military and diplomatic support that allows the genocide to continue.
Gaza is not simply another version of the GWOT. But the political logic is recognisable. Terrorism becomes more than a crime or military threat. It becomes a condition under which normal restraints can be suspended - even one under which genocide can be justified in the language of security.
The US-Israeli war on Iran has revived another defining feature of the post-9/11 era, namely the crime of preventive war.
In February, the US and Israel attacked Iran amid under the guise of negotiations over its nuclear programme, wiping out its entire leadership, bombing civilian targets, most deplorably a girls school, and civil infrastructure. The war has since spread across the region, with Iran attacking US bases and neighbouring pro-US Arab states and fighting engulfing the economically vital Strait of Hormuz.
Once again, the language is strikingly familiar - nuclear danger, terrorism, national survival and a threat that cannot be allowed to materialise.
This was one of the central ideas behind the GWOT, namely that waiting for a threat to become imminent could itself be too dangerous.
Twenty-five years after 9/11, the War on Terror has therefore taken two different paths. In the West, its security politics have increasingly been redirected from terrorists towards migrants and other supposed internal enemies. In the Middle East, many of its original assumptions about preventive war, existential threats and exceptional violence remain alive.
When the rules stop being universal
Vladimir Putin shows how the same era also helped weaken the international order from another direction.
Putin initially enthusiastically embraced the GWOT. Russia was already waging a brutal war in Chechnya when 9/11 occurred, and he rapidly recast Moscow's campaign as another front in the global struggle against terrorism. Bush, in turn, described Putin as a partner in that struggle.
But by Putin's 2007 Munich Security Conference speech, Russia was openly attacking the US-led order and accusing Washington of violating international law.
The War on Terror had given Putin both an opportunity and, later, an alibi. Russia borrowed its language of existential security while pointing to Iraq and US exceptionalism as proof that the liberal international order was hypocritical.
That does not mean Iraq justifies Russia's invasion of Ukraine. It does mean the US weakened the very principles needed to condemn such aggression consistently.
Gaza has deepened that crisis further. When Western governments invoke sovereignty, international law and civilian protection in Ukraine while giving Israel the means to devastate Gaza, the damage goes beyond charges of hypocrisy.
If the rules depend on who is breaking them and against whom, they stop being universal rules at all.
Before 9/11, the US emerged from the Cold War claiming to lead a liberal world order grounded, however imperfectly, in international law, human rights and democratic government.
The GWOT did not destroy that order. It fractured it.
Its deeper tragedy is that the Bush administration believed US power could be used not simply to defeat terrorism, but to preserve and spread liberal democracy. Torture, rendition, indefinite detention and illegal war were justified by supposedly liberal ends.
Twenty-five years later, even the ends have changed.
The ascendant illiberals of our age do not promise to improve the liberal order. They promise to replace it: universalism with ethno-nationalism, international law with raw sovereign power, multiculturalism with civilisational identity, and the restraints of liberal democracy with the permanent demands of "security".
Nor is this solely the work of those who openly seek liberalism's destruction. As during the GWOT, the rise of illiberalism has also been made easier by governments that defend international law selectively, tolerate its violation by allies and then wonder why appeals to the "rules-based order" carry less and less weight.
Modern illiberalism would almost certainly have emerged without 9/11. But the response to those attacks hastened its rise, furnished it with powerful political tools and helped knock the world off its liberal democratic axis.
Perhaps the most enduring legacy of 9/11 and the War on Terror is therefore neither Afghanistan nor Iraq, but the spread of its central proposition: when the threat is grave enough, the rules no longer apply.
Twenty-five years after the towers fell, the state of exception has escaped the emergency that created it.
The enemies have multiplied, the exceptions are becoming the rule, and the world that once proclaimed the inevitable triumph of liberal democracy increasingly resembles an age of monsters.
Sam Hamad is a writer and History PhD student at the University of Glasgow, focusing on totalitarian ideologies.
Join the conversation: @The_NewArab (https://twitter.com/The_NewArab).
Have questions or comments? Email us at: editorial-english@newarab.com
Opinions expressed in this article remain those of the author and do not necessarily represent those of The New Arab, its editorial board or staff.