Tragic events sometimes bring out the best in people.

That was certainly true on September 11, 2001. In Greenwich Village, where I lived, people at New York University provided food and coffee, lent the survivors telephones, or walked them to the local hospital. Though the event was horrific, the response of New Yorkers was not unusual. Cooperation is built into human beings; we begin to practice it at the very onset of life in relations with those who take care of us, and we draw on that capability all through our lives at work, in our communities, and in our own parenting.

But if cooperation is as deeply embedded in us as competition, it's nonetheless a fragile experience, because it requires a good measure of trust in and openness to others. Looking back, I'm struck by how briefly that openness lasted. Within a year, New York had become a locked-down city. The changes showed in small things, like new security checks in buildings, loudspeakers warning people in the subways to be suspicious, and police searches of anyone who looked foreign. Nationally, a regime of fear took hold, and that regime has lasted.

The reasons for this change in civic life are both political and social. Politically, the Bush administration seized on 9/11 to restart the war in Iraq that had been abandoned a decade earlier; the political war depended in large part on the climate of fear for its legitimacy. Fear comes in two forms. One arises from a clear-cut enemy who can be fought in clear-cut ways. The other gathers around dread, a generalized sentiment of vulnerability that is hard to contain rationally. The Bush administration capitalized on dread; its war on terror depended on an ill-defined sense of threat, just as occurred a half-century before, in the McCarthy era.

To me, the Tea Party movement is grounded in the pervasive fear of the outsider—the external threat now located domestically rather than internationally. Unease about big government has long infused the American right; Tea Party sentiment is special because of its intensity, which owes, I think, to that sense of uncontained vulnerability—to dread. Like the older right, the Tea Party insists on the liberty of individual citizens, but this insistence now has an almost hysterical quality; its intense feelings of violation make this movement the child of the war on terror.

The legacy of 9/11, though, can't be viewed only through the prism of the American right. The event's impact has been connected to the other great trauma of the past decade, the great economic meltdown, with its millions of impoverished people out of work or caught in no-future jobs. In a study I recently did of middle-class, unemployed workers, I was struck by what amounts to the uncontained dread felt by my subjects, as though there were no boundaries to the threats they faced. The sentiment has led many, ironically, to want to go back to the ancien régime, to the old competitive, individualized economic conditions that caused so much subsequent pain. What's missing is a desire to create new forms of mutual support or new institutions. In this, socially as well as politically, the aftermath to 2008 differs sharply from society's response in 1932, when economic collapse spawned the New Deal.

The two traumas of the past decade are connected: In both, dread has caused people to withdraw into their shells rather than cooperate with and support one another. The impulse to cooperate, as evinced in the immediate response to 9/11, is natural to us as social animals. But society and politics can, and have, subverted this natural impulse. The decade has been one in which unfocused fear, with its malign brother indiscriminate anger, has driven us away from one another.

Richard Sennett is a professor of sociology at New York University and at the London School of Economics and Political Science. His next book, Together: The Rituals, Pleasures, and Politics of Cooperation, will be published by Yale University Press in November.


Also in this special issue:
Charles Kurzman asks: Where are the Islamic terrorists?
Evan R. Goldstein explores an oral-history archive.
Jacques Berlinerblau reflects on Ground Zero.
Peter van Agtmael captures images of 9/11's aftermath.