In a letter to one of his victims, the mysterious terrorist called the Unabomber warns of the evils of technology.
On a Michigan farm, as he is allegedly plotting the Oklahoma City bombing, Timothy McVeigh complains bitterly to neighbors that the U.S. government has become a tyrannical force.
They operate at very different extremes -- the Unabomber declaring himself a left-wing anarchist, and McVeigh drawn to the growing militia movement on the right -- but they seem to share a fundamental fear: A monolithic world order is robbing individuals of control.
"Whether it's the technological elite or the government, it's the same basic idea," said Tom Tyler, head of the social psychology group at the University of California at Berkeley. "It's an exaggerated idea of a kind of secret, all-powerful group that's controlling people's lives."
Although such views are typically marginalized as paranoid or fringe, some experts say they are merely the extreme expressions of a broader social malaise that also drives more "mainstream" movements, such as the backlash against immigrants.
Americans, the analysts say, feel rootless and powerless. Faced with worrisome changes
brought about by rapid technological advances, economic upheaval and the end of the Cold War, they are losing faith in basic social institutions -- government, big business and the media.
"This kind of extremism usually comes during times of perceived threat and ambiguity, where people are not exactly sure what's happening," said social psychologist John Dovidio of Colgate University. "We have a society that's in moral chaos. Our values are shifting in ways it's hard for anybody to feel comfortable with."
Experts often relate such anxieties to turbulent economic times, when people feel shut out of job opportunities or excluded from the mainstream. Economic insecurity is a common explanation for the recent rise of citizens' militias and hate groups.
Although the Unabomber seems less motivated by economic worries, his vision of computers taking over the world manifests a similar fear of being left behind, said sociologist Seymour Martin Lipset at George Mason University in Virginia.
Disdain for big business, big government -- and by extension, "big technology" -- is nothing new in America, said Lipset.
"It declined sharply during the Depression and the New Deal," he said. "But since the Second World War, things have been reverting back to the classic American fear of the state. . . . This is the most anti-statist country in the developed world."
Most people cope with troubled times without resorting to violence. But their fears may emerge in other ways.
"If we looked at more typical citizens who might be distrusting their government, the way that's getting manifested are things like the anti-immigration initiative, and 'three strikes, you're out,' the idea that we've got to have order and stop these people from destroying our society," said Tyler at UC Berkeley.
Psychologists typically distinguish between normal people and a small number of individuals who make some claim to the moral high ground to justify harming others. But, some warn, these extremists are really on a continuum with the rest of society and cannot simply be dismissed.
"I get nervous when it is said that these people are nuts, it doesn't reflect anything, it's just these crazies," said University of California at Santa Cruz psychology professor Thomas Pettigrew. "They said the same thing about people who desecrated Jewish synagogues. They always said that about the Klan."
While most experts agree that the recent acts of terrorism on U.S. soil are somehow a sign of the times, there is little consensus about what they portend.
One school of thought predicts that society will grow increasingly intolerant -- and violent.
"We know that in Germany, the hyperinflation of the 1920s produced enormous insecurity in the middle class, then the depression broke open, the boundaries of society fell apart and the Nazi party came to power," said social psychologist Raphael Ezekiel at Michigan University.
"A big part of what they were doing was creating violence in the streets, then saying, 'Look, the government can't protect us from violence in the streets.' "
Others, such as Dovidio, say that the current rise in extremism reflects the ebb and flow of society and that tragedies like the Oklahoma bombing may actually inspire a search for greater harmony.
"Society has in general a self- corrective nature," said Dovidio. "Crises develop, kind of the flash points, and those crises help to bring people together again and develop a new sense of direction and coherence."