Hijacked United Airlines Flight 175 from Boston crashes into the south tower of the World Trade Center and explodes at 9:03 a

September 11, 2011

Ten Years After the 9/11 Terrorist Attack

Hijacked United Airlines Flight 175 from Boston crashes into the south tower of the World Trade Center and explodes at 9:03 a.m. on September 11, 2001 in New York City. (Spencer Platt/Getty Images)

Ten years after 9/11, the United States and its allies remain at war against al Qaeda and associated militant Islamist groups. Recent successes, like the deaths of Osama bin Laden and other prominent leaders, have led some to assume that the terrorist threat has diminished. The long war, however, is far from over, and the challenges the United States faces emanate from not only Afghanistan and Pakistan but also Yemen and Somalia. The Critical Threats Project evaluates the current threat environment ten years after the 9/11 terrorist attacks and provides a list of resources on the global al Qaeda threat.


ten years later: the al Qaeda threat today

Maseh Zarif, A Still-Dangerous World

"This regional environment today is underappreciated. Acknowledging these challenges and the risks they pose should, in fact, be prerequisites for any serious policy debate. Only through an understanding of the threats present can we begin to ask the key questions that should be guiding policy decisions going forward. Debates over the national debt, the prosecution of the current wars, and America’s commitments to its allies, for example, are among the issues that require such an accounting."

Katherine Zimmerman, Ten Years After 9/11: Al Qaeda's Reemergence in Yemen

"The strategic objective of defeating AQAP and its like-minded affiliates in Yemen cannot be achieved solely through the removal of AQAP’s top leadership. Yemen’s environment permitted al Qaeda to re-emerge stronger after its leadership was removed in the early 2000s. Conditions in Yemen, even before the outbreak of the Arab Spring, are favorable for al Qaeda’s operations. The expansion of AQAP’s operating space during the Arab Spring underscores the importance of denying all al Qaeda groups safe haven."

 Reza Jan, Diversified, Not Diminished: Al Qaeda in Pakistan Since 9/11

"Although personally diminished, al Qaeda’s core group has found new ways of expanding its lethality: it has succeeded in innervating other groups with the means to conduct violence in its name, causing the brand to supersede individual membership in importance. While al Qaeda’s traditional structure has deteriorated over the years, the threat emanating from Pakistan to the region, and the world, is diversified rather than diminished."


Additional resources on al qaeda and the al qaeda network

Frederick W. Kagan, The Threat to the U.S. Homeland Emanating from Pakistan

"The worst thing we could do now would be to take bin Laden’s death or the progress made to date in Afghanistan as an excuse to withdraw forces prematurely, thereby easing the pressure on militant Islamist groups in Afghanistan just as we would otherwise approach the point of maximum pressure on them and those who support them. Now is the time to reinforce success by exercising patience in Afghanistan and allowing the strategy designed to persuade everyone in Afghanistan and in Pakistan that the militant Islamists in Afghanistan will fail to continue to work."

Frederick W. Kagan and Kimberly Kagan, Success Against al Qaeda Depends on Success in Afghanistan

"It is faulty logic of the worst kind to take the situation in Afghanistan that makes it so inhospitable to al Qaeda as a given, regardless of the presence or absence of U.S. forces or their activities. If the U.S. withdraws prematurely from Afghanistan and the country collapses again into ethnic civil war, then al Qaeda will have regained its original and most dangerous sanctuary."

Frederick W. Kagan and Kimberly Kagan, Bin Laden Is Dead

"Withdrawing forces from Afghanistan and cutting all aid to Pakistan would merely reinforce two of the most prevalent conspiracy theories in South Asia—that the United States will always abandon those who rely on it, and that we were only there to get bin Laden anyway."

Various authors, Osama Bin Laden's Death

"Al Qaeda founder Osama bin Laden’s death is an important milestone. The broader struggle against the al Qaeda network and militant Islamism in general, however, has by no means ended."

Adam Kahan, Al Shabaab's Rise in the al Qaeda Network

"Somalia’s militant Islamist group al Shabaab provides a safe haven to senior al Qaeda operatives and is establishing operational ties to al Qaeda’s most active affiliate in Yemen. The group’s rise, its ambitions beyond Somalia, and recent signs that it is garnering greater attention from al Qaeda Central leaders suggest that al Shabaab is an increasingly key player in the al Qaeda Network."

Maseh Zarif, Al Qaeda's Safe Haven in Iran

"The operability of the network confirms that the Iranian regime is directly facilitating al Qaeda activity in the region, including coordinating with al Qaeda’s representative in Iran to arrange the release of al Qaeda members from “detention.” This arrangement, in place since 2005, further demonstrates the Iranian regime’s willingness to discount the Sunni-Shi’a sectarian divide if it can help inflict harm on American security and interests."

Reza Jan, Ilyas Kashmiri: The Possible Death of an al Qaeda Mastermind

"Given the seniority of Kashmiri’s position within the al Qaeda network and his active role in plotting attacks, his death, if true, would be a major setback for al Qaeda, especially with it coming so close on the heels of the death of Osama bin Laden. If Kashmiri is alive, however, it means that one of al Qaeda’s most dangerous operatives remains a threat at large."

Katherine Zimmerman, Al Qaeda's Gains in South Yemen

"The fall of Aden raises the possibility of the fall of the south, which will have resounding effects on the future of the Yemeni state. Al Qaeda would gain relative freedom of movement from the Arabian Sea to the Saudi border, significantly increasing the risk of an attack on an international or Saudi oil target, and could erect a form of an Islamist government in its territories. The Yemeni state would not only lose its southern port city of Aden, but would also lose revenues from southern oil. Should the Yemeni military or some other actor fail to halt al Qaeda’s advance, there is the very real prospect that al Qaeda could establish an Islamic emirate in south Yemen."

Frederick W. Kagan, Al Qaeda's Yemen Strategy

"AQAP seems to be attempting to carve a broad territorial corridor out of the historic heart of Yemen, with the aim of linking the southern Yemeni ports on the Gulf of Aden and the Arabian Sea with the traditional pilgrimage and trade routes in southern Saudi Arabia. The aim of this strategy would seem to be the creation of a terrorist highway of sorts that would facilitate attacks on the Islamic holy cities in the Hijaz, Riyadh and the Najd, and the oil and gas infrastructure located in the Saudi Eastern Province, the United Arab Emirates, and Qatar."

Katherine Zimmerman, Examining the Potential Relocation of al Qaeda Leadership

“Yemen and Somalia could both offer some sort of sanctuary to the al Qaeda leadership, but the decision to remain along the Afghanistan-Pakistan border is an indication that it does not sense an immediate threat to its survival. Transferring or gaining access to an established support network will take time without pre-existing, vetted networks in place.”

Charlie Szrom and Chris Harnisch, Al Qaeda's Operating Environments: A New Approach to the War on Terror

“Territory matters to al Qaeda, notwithstanding the arguments of some counterterrorism experts to the contrary. Understanding the importance of territory to the al Qaeda network and the precise nature of its various operating environments could lay the foundation for a detailed strategy, help educate Americans about the war on terror, and inform a reexamination of US policy in the war on terror.”

Maseh Zarif, Dusseldorf al Qaeda Cell

“The Dusseldorf cell leader’s reported link to al Qaeda sanctuaries in Pakistan is part of a long-recurring pattern in al Qaeda’s operations against the West… as the cell leader’s travel destination again demonstrates, the threat from al Qaeda originates from foreign sanctuaries, such as those in the Afghanistan-Pakistan border region.”

Frederick W. Kagan and Katherine Zimmerman, Yemen Strategic Exercise

“Not only is Yemen unlikely to see a smooth transition to a stable new regime, but its new leaders are singularly unlikely to see pursuing al Qaeda in the Arabian Peninsula on America’s behalf as a high priority for some time.”