It is as if the United States knew not what to do with victory.

In late 2001, clandestine U.S. intelligence officers and Special Operations advisers, galloping alongside Afghan tribal horsemen and supported by U.S. airpower, ousted the Taliban regime and rousted al Qaeda from its Afghan haven. It was a dazzling campaign hailed as an innovation in modern warfare. But as soon as victory was achieved, it seemed to start slipping away.

The authors in this section offer contrasting explanations for what went wrong. For U.S. Ambassador James Dobbins, who helped negotiate the Bonn agreement forming the new Afghan government...

The September 11, 2001, attack on the World Trade Center and the Pentagon was unprecedented in the scale of its destruction and the immediacy of its visual impact. Americans had heard or read about other historical disasters, but this was the first to be witnessed by hundreds of millions of citizens as it occurred. The impact on American policy was correspondingly dramatic and long lasting. The immediate impulse was to identify and make pay those who were responsible for the assault. There was an equal determination to make sure that such an attack could never be repeated. But both that...

Small teams of CIA and U.S. Special Operations Forces advisers, working closely with local Afghans, overthrew the Taliban regime in Kabul on November 14, 2001.¹ It was not an invasion. Afghans did all the fighting on the ground, supported by American airpower and high technology, a campaign that has been hailed as an innovation in modern warfare.² By making alliances with key Afghan leaders and bringing to bear very intimidating lethal force when needed, these small teams were able to exert political and military influence greatly disproportionate to their number. As soon as victory was achieved, however, the United States...

I stepped off a Blackhawk helicopter in early 2011 in Bermel, Afghanistan, several miles from the border with Pakistan’s North and South Waziristan Agencies. The jagged limestone mountain ranges, cavernous gorges, sparse population, and parched landscape make it inhospitable terrain and an ideal place for a terrorist sanctuary. As I had witnessed on previous trips, the area has a haunting, isolated feel. “The quietness of the place is uncanny,” wrote T. E. Lawrence, better known as Lawrence of Arabia, during a short visit in the 1920s, “no birds or beasts except a jackal concert for five minutes about ten p.m.”...

Common wisdom suggests that the Iraq War was an egregious instance of strategic overreach by America—a bridge too far in the struggle against terrorism, which had uniformly deleterious effects. The invasion and the botched occupation, the narrative goes, injected new life into al Qaeda at precisely the point when its safe havens were under attack and its strategy of attacking the “far enemy” was under fierce criticism from even diehard supporters. Yet this assessment, while accurately describing the period of 2003 to 2006, is only half of the picture. From 2006 to the close of the U.S. drawdown in...

It is remarkable how much of the war against violent jihadist terrorism is waged on an intangible battleground. Fueled by ideology, the terrorists take aim at psychology. Meanwhile, one of the most formidable counterattacks could come from theology.

“At its core the challenge of radical Islamism is ideological,” writes Angel Rabasa. “To prevail against the challenge of radical Islamism, therefore, it is necessary to address comprehensively the ideological challenge that it presents—the content or substance of the ideology, its ideological agents, networks, and means of dissemination—and to devise effective countermeasures for each of these components.” Rabasa argues for...

For the United States, the threat of global terrorism defined the security environment in the first decade of the 21st century. After 9/11, the U.S. government developed a National Strategy for Combating Terrorism that declared that the 9/11 attacks were acts of war against the United States and that combating terrorism and securing the U.S. homeland were the country’s top priorities. Homeland defense was not considered sufficient to safeguard the United States. Central to the Bush administration’s conception of the war on terrorism was the need to carry the war to the terrorists in their own lairs. As the 9/11...

At the heart of al Qaeda’s effort to build a violent social movement based on its transnational ideology of salafi jihadism—a violent fundamentalist form of Islamism—is a contest over the true nature of Islam: whether Islam is merciful, compassionate, and tolerant, imposing substantial constraints on the permissibility of violent jihad, which is the view of most mainstream Muslim thought, or whether Islam is intolerant and permissive of violent jihad, in accordance with al Qaeda’s reading.¹ This contest has aptly been described both as a civil war within Islam itself² and as being analogous to the West’s own centurylong...

We live at the edge of doom. President Obama has declared that “the single biggest threat to U.S. security, . . . near-term, mid-term, and long-term, would be the possibility of a terrorist organization obtaining a nuclear weapon.”¹ According to Harvard University political scientist Graham Allison, who has emerged as the nation’s leading voice of concern about nuclear terrorism, there is “better than a 50 percent chance that terrorists will detonate a nuclear bomb in the United States within ten years”² (that is, by 2014). A national commission on weapons of mass destruction concluded that there is a “better than...

Since 9/11, Americans have had to think differently about warfare, suggests Christopher Paul. The reality of asymmetric warfare, the fact that not all conflicts can be won through force alone, and the contested superiority of American values—these factors have grown more prominent over the past decade, making warfare today more complex, at least tactically, than it was before.

“Whether fighting terrorists or insurgents,” writes Paul, a combatoriented approach alone “does nothing to address the underlying popular motives that lead to terrorist or insurgent movements in the first place.” In such conflicts, America needs to extend “both a closed fist...

The 9/11 terrorist attacks have changed how Americans think about war by emphasizing different challenges. My research on counterterrorism and counterinsurgency has highlighted three of these newly salient (though not new) challenges and what they mean for America as it attempts to win the war, not just the battles, against terrorist foes. In brief, these newly salient changes have required America to use both a closed fist and an open palm at the same time, winning the physical battles while addressing the grievances of, and reaching shared understandings with, those who support America’s adversaries.

The first challenge is that the...

It was spring 2009 when I met some friends for dinner and drinks in Washington, D.C. The topic of conversation was the Obama administration’s new strategy for Afghanistan and Pakistan. Two of us were terrorism researchers, a third worked for the U.S. Department of Defense, and the fourth had just spent a year in Pakistan. We were asking ourselves, Is this fight truly about Afghanistan, or is it about al Qaeda? And if it is about al Qaeda, does the new White House strategy go far enough?

At the time, similar conversations were occurring in the hallways of U.S. government...

They say a picture is worth a thousand words. In 2004, news broke that U.S. prison guards at Abu Ghraib were abusing and humiliating Iraqi detainees. The pictures that vividly told the tale went viral. U.S. casualties in Iraq immediately spiked. For years afterward, the Abu Ghraib scandal was a rallying cry and motivator for foreign fighters who streamed into Iraq to martyr themselves in suicide operations.

Ten years after 9/11, al Qaeda is still an inspiration and proverbial destination for far too many terrorist recruits. A mainstay motivation of extremists has been the perception that the West, and the...

In reaction to 9/11, Americans not only demanded immediate action to prevent future terrorist attacks but also kindled expectations that “could not be satisfied by any realistic homeland security policies,” writes Brian Jackson in his history of post-9/11 America. “Fear drove action,” he concludes, “and political rhetoric frequently stoked rather than cooled the flames of urgency.”

Even as time passed, the sense of urgency persisted, as if the nation had been overrun by day traders. “Just as the chief executive officers of public companies complain that their investors demand short-term performance improvements on a quarterly basis, making it impossible to...

The 9/11 terrorist attacks were neither the first incidents of terrorism on U.S. soil nor even the first attacks on the World Trade Center or the Pentagon. In 1993, the World Trade Center was attacked with a vehicle bomb by Ramzi Yousef, a prolific terrorist subsequently connected to major plots aimed at the aviation system. Decades before, in 1972, the Weather Underground, a domestic group, successfully detonated a bomb inside the Pentagon. Previous domestic terrorist attacks had also resulted in numerous casualties; one such attack, the bombing of the Murrah Federal Building in Oklahoma City in 1995, killed and injured...

The phrase “touch my junk” became part of the lexicon of air passenger security in late 2010 thanks to the controversial decision by the U.S. Transportation Security Administration (TSA) to increase the physical scrutiny of air travelers. John Tyner, attempting to fly from San Diego, uttered the now-famous words when he refused to walk through a whole body image (WBI) scanner and subsequently also refused to submit to a full-body frisk. The latter would have involved a TSA agent touching his “junk,” or genitals.

That national attention focused on the anatomy of a private citizen is one small indication of...

September 11, 2001, marked a sea change for U.S. intelligence, one that is widely acknowledged but far from fully grasped. The reversal in the priority of targets—from nation-states to transnational groups, such as terrorists—is widely acknowledged. But this change goes to the heart of how intelligence does its business: from collection to analysis to dissemination. The change is nicely captured in a line given to me by a young analyst at the U.S. National Geospatial Intelligence Agency: “Imagery used to know what it was looking for and be looking for things; now it doesn’t know what it’s looking...

There is a tendency within American history to draw inspiration from devastation, hope from misfortune, optimism from hardship. It is a tendency rooted in the American experience of having carved meaning and virtue out of a vast new frontier. It remains integral to the identity of this nation, founded and often reinvigorated by immigrants, to deem the struggle of displacement worthwhile for the sake of a better life for those who will follow. It is an abiding faith of a people who believe they are destined to shine a light, a beacon, a torch of freedom for the world.

The...

The 9/11 attacks, along with the anthrax attacks that soon followed, were an important wake-up call for America’s leaders, including the leadership of America’s public health system. That system had become in part a victim of its own success by all but eradicating a string of devastating diseases, including smallpox and polio. Public health agencies, especially those at the state and local levels, were thought to be overstaffed and therefore were targeted for budget cuts. Things got so bad that a 1988 Institute of Medicine report bluntly concluded, “The public health system is in disarray.” Fourteen years later, the situation...

The focus of much of the nationwide debates on homeland security and foreign policy sparked by 9/11—debates on everything from an Islamic community center near Ground Zero to the war in Iraq—has been on the prevention of future attacks. Largely overlooked in efforts to enhance national security has been a basic question: When Americans are injured or killed or when their property is damaged by terrorists, who, if anyone, should pay to cover the losses? The answer to this question can have important implications for the resilience of the country’s economy and society to terrorist attacks. It can...

Testifying before the U.S. Senate in December 2001, when three months had passed with no further terrorist attacks, I was asked if we were “through it yet.” I thought not. The United States had just begun the campaign in Afghanistan to crush the group responsible for the most devastating terrorist attacks in history, and in my view it was likely to take years. The question might better be asked today, a decade later. America is now in the tenth year of what was initially called the “Global War on Terror,” while the conflict in Afghanistan, a component of that new...