SPECIAL REPORT
Twenty five years after the September 11, 2001 terrorist attacks, the world has changed profoundly. The attacks that killed nearly 3,000 people in New York, Washington and Pennsylvania transformed the international security environment and triggered the most sustained global campaign against terrorism in modern history.
The United States and its allies invaded Afghanistan, dismantled much of Al Qaeda’s original leadership structure, hunted down its senior commanders, disrupted terrorist financing, strengthened intelligence cooperation and fundamentally changed aviation, border and homeland security. Yet, 25 years later, terrorism has not been defeated.
The most visible measure of success has been the destruction of the terrorist leadership responsible for 9/11 and the subsequent dismantling of the centralized Al Qaeda network that once operated with relative freedom. Osama bin Laden was killed in Abbottabad, Pakistan, in May 2011. His successor, Ayman al-Zawahiri, was killed in a US drone strike in Kabul in July 2022.
The same campaign eliminated many of the most notorious leaders of the jihadist movement. Abu Musab al-Zarqawi, the founder of Al Qaeda in Iraq, was killed in 2006. Abu Bakr al-Baghdadi, leader of ISIS, was killed in Syria in 2019, followed by several of his successors. In Yemen, Anwar al-Awlaki, Samir Khan, Nasir al-Wuhayshi and Qasim al-Rimi were eliminated. In Somalia, Ahmed Abdi Godane, the leader of Al Shabaab, was killed in 2014, while senior ISIS commander Bilal al-Sudani was killed in 2023.
Nigeria has also experienced the decapitation of several generations of terrorist leadership. Boko Haram founder Mohammed Yusuf was killed in 2009. Abubakar Shekau died in 2021 after a confrontation with ISWAP. Mamman Nur was killed in 2018, while Abu Musab al-Barnawi was later reported killed. Other senior commanders have been eliminated through Nigerian military operations, including Abu Fatima and several other Boko Haram and ISWAP commanders. In 2026, Nigerian and US forces also reported the killing of Abu-Bilal al-Minuki, also known as Abu Mainok, described as a senior ISIS figure involved in global operations.
These successes matter. They demonstrate that terrorist organizations can be disrupted, leaders can be hunted down and territorial ambitions can be defeated. The destruction of the ISIS territorial caliphate in Iraq and Syria by 2019 was particularly significant. Mosul and Raqqa were liberated, and ISIS lost the territory from which it had proclaimed itself a state.
But the destruction of territory did not mean the destruction of terrorism.
The central lesson of the past 25 years is that terrorism is remarkably adaptive. When hierarchical organizations are destroyed, they fragment. When leaders are eliminated, successors emerge. When territory is lost, fighters return to clandestine operations. When conventional communications become dangerous, terrorists move to encrypted platforms and decentralized networks.
Al Qaeda today is considerably weaker than it was before 9/11, but it has not disappeared. Its regional affiliates have become increasingly important, particularly Al Shabaab in Somalia, Al Qaeda in the Arabian Peninsula in Yemen and Jama’at Nusrat al-Islam wal-Muslimin, JNIM, across the Sahel.
ISIS has followed a similar pattern. Although its territorial caliphate is gone, ISIS remains active through branches in Afghanistan, Africa and the Middle East. ISIS Khorasan remains a serious threat in Afghanistan, while Islamic State affiliates operate in the Sahel, Somalia and Central Africa. In Nigeria, ISWAP remains one of the most dangerous terrorist organizations in the Lake Chad region.
Boko Haram factions also remain active. Other terrorist organizations, including Tehrik-e Taliban Pakistan, Ansaru, Lashkar-e-Taiba and Jaish-e-Mohammed, continue to demonstrate that the global terrorist threat is much broader than the organizations responsible for 9/11.
The geographical centre of gravity has also shifted.
Africa has become one of the most important theatres in the global fight against terrorism. The Sahel has experienced a particularly dangerous expansion of jihadist violence, with JNIM and Islamic State affiliates exploiting weak governance, porous borders, local grievances, ethnic tensions, poverty and competition over land and resources.
The 2026 Global Terrorism Index ranked Nigeria as the world’s fourth most affected country by terrorism. Nigeria recorded 750 terrorism-related deaths in 2025, a 46 percent increase from the previous year, while Borno State accounted for the majority of attacks and deaths. ISWAP and Boko Haram factions were responsible for most terrorism-related deaths in the country.
This should force a fundamental reconsideration of what victory means.
The war against terrorism cannot be measured only by the number of terrorist leaders killed. Leadership decapitation is important, but it does not automatically destroy the ecosystem that produces terrorism. A terrorist organization can survive the death of its leader if its ideology, financing, recruitment networks, local alliances and grievances remain intact.
This is particularly evident in Africa. Terrorist groups increasingly operate at the intersection of terrorism and organized crime. Kidnapping, extortion, illegal taxation, arms trafficking, smuggling and control of local economies can finance insurgencies while simultaneously giving armed groups influence over communities.
Nigeria’s security environment demonstrates the complexity of this evolution. Banditry in the northwest and north central regions is not synonymous with jihadist terrorism, but criminal networks and terrorist organizations can exploit the same weaknesses, including ungoverned spaces, porous borders, illicit economies and limited state presence.
Technology has also transformed the battlefield.
The post-9/11 era produced extraordinary advances in intelligence fusion, biometrics, surveillance, drones, satellite imagery, cyber operations and financial tracking. These capabilities have made it considerably harder for large terrorist organizations to operate openly.
But the same technological revolution has lowered the barriers to terrorism. Social media allows extremist propaganda to cross borders instantly. Encrypted communications facilitate clandestine coordination. Commercial drones provide cheap surveillance and attack capabilities. Artificial intelligence could further accelerate propaganda, recruitment and operational planning.
The threat has therefore become more decentralized. The world is no longer dealing only with large organizations with identifiable headquarters and leadership structures. Small cells and lone actors can cause significant casualties without requiring the infrastructure once associated with major terrorist attacks.
Afghanistan provides another important lesson. The US military intervention removed Al Qaeda’s sanctuary and eventually killed bin Laden, but the two decade war ended with the Taliban returning to power in 2021. ISIS Khorasan remains a violent opponent of the Taliban, while concerns about extremist networks operating from or through Afghanistan remain part of the international security equation.
Iraq provides a similarly complicated lesson. The overthrow of Saddam Hussein removed one regime, but the instability that followed contributed to the rise of Al Qaeda in Iraq, which eventually evolved into ISIS. The experience demonstrated that military victory without a durable political and institutional settlement can create conditions for new forms of extremism.
Yet not every terrorist organization has survived.
Some disappeared through military defeat, political settlement, internal collapse or transition into political structures. ETA ended its armed campaign and subsequently dissolved. The FARC transitioned from insurgency to political participation following Colombia’s peace agreement. Aum Shinrikyo was effectively dismantled through arrests and legal action.
These cases demonstrate an important reality: terrorism can end, but the pathway to its end is not always military.
Twenty five years after 9/11, therefore, the world has achieved enormous tactical successes but has not achieved strategic victory.
The United States and its allies prevented another attack on the scale of 9/11 on the American homeland. They destroyed terrorist sanctuaries, eliminated major leaders, dismantled the ISIS caliphate, disrupted financing and built security systems that did not exist before September 2001.
But terrorism has mutated rather than disappeared.
The principal challenge today is no longer simply finding the next Osama bin Laden. It is preventing terrorist organizations from exploiting weak states, unresolved conflicts, criminal economies, political grievances, poverty, porous borders and technological vulnerabilities.
The war has consequently moved from one against a relatively identifiable global network to a far more complicated struggle involving insurgencies, terrorist franchises, criminal networks, ideological movements and increasingly decentralized actors.
The lesson of the past quarter century is therefore neither that the war against terrorism has failed nor that it has been won.
It is that the world has made substantial progress, but the nature of the threat has changed.
The greatest danger now may not be another 9/11. It may be the gradual normalization of terrorism in places where weak institutions, insecurity and criminal economies allow extremist organizations to become permanent features of the political and security landscape.
Military power remains indispensable, but it cannot by itself produce lasting security. Counterterrorism must increasingly be combined with effective policing, intelligence, border management, financial controls, accountable governance, economic opportunity, community resilience and political solutions to conflicts that terrorists exploit.
Twenty five years after 9/11, the world is undoubtedly better prepared than it was in 2001. But it is not a world without terrorism.
The war against terrorism has entered a new phase: less about defeating one global enemy and more about preventing a constantly evolving collection of terrorist organizations and criminal extremist networks from acquiring the capacity, legitimacy, territory and technology to threaten states and societies.
That is the unfinished war.
Capt. Bishop C. Johnson, US Army (rtd), is a national defense and military strategist, and a political commentator.
Gatekeepers News is not liable for opinions expressed in this article; they’re strictly the writer’s.
