Or kill doctors and receptionists at abortion clinics.

Or plant nerve gas in a subway full of defenseless commuters.

Or offer a million-dollar reward for the assassination of a "blaspheming'' author.

Or hole up with automatic weapons in a Waco doomsday cult, ready to fight the outside world.

Or shoot high school girls in the face in Algeria because they aren't wearing veils.

Or machine-gun Hindu weddings in Punjab to gain a Sikh theocracy, the Land of the Pure.

Or bomb the World Trade Center as a symbolic strike against "the Great Satan.''

The April 19 horror in Oklahoma City was the latest and largest reminder that True Believers are a very real peril, even if normal people can't understand them. The bombers think their cause is more important than the lives of preschool tots and office workers. To them, mass murder is justified to deliver their vengeful message. To the rest of us, it's madness that someone would make elaborate secret plans to massacre children as a public demonstration.

Now that the Cold War is over, this kind of danger has taken the spotlight as a menace of the 1990s. A dozen car bombings have killed about 300 unsuspecting victims around the world in the past two years -- and the poison gas attack in Tokyo's subway added a new dimension to the danger.

It's perplexing that some of the fanatics are intelligent and possess high technical skills. Many adherents to Japan's Supreme Truth cult, suspected in the subway gassing, are college graduates. Yet they kissed their guru's big toe, paid $2,000 each for a sip of his bathwater, and paid $10,000 for a drink of his blood. What's going on here?

What's the pathology behind killing innocent strangers to make a statement? In his classic book, The True Believer, Eric Hoffer said zealots go through an emotional process of renouncing their individuality, and finding identity in a violent cause. Hoffer wrote:

"The fanatic is perpetually incomplete and insecure. He cannot generate self-assurance out of his individual resources -- out of his rejected self -- but finds it only by clinging passionately to whatever support he happens to embrace. This passionate attachment is the essence of his blind devotion and religiosity, and he sees in it the source of all virtue and strength.... He easily sees himself as the supporter and defender of the holy cause to which he clings. And he is ready to sacrifice his life.''

This explanation may be helpful to psychiatrists, but it can't placate the shattered families of Oklahoma City.

Religion is entwined in much murder by fanatics, but the Oklahoma tragedy seems to involve cultism tied more to guns than to scriptures. America has a variety of oddball, far-right, armed, covert groups -- neo-Nazis, tax-haters, "skinheads,'' white-supremacists, the Church of the Aryan Nations, survivalists, "Christian Identity'' adherents -- all calling themselves patriots. Fundamentalist preachers and gun dealers rank among their leaders.

In the past, these would-be Storm Troopers seemed more goofy than deadly. Now, they've spawned what Harvard psychiatrist Robert Coles calls "the craziness of hate.''
Apparently, the Oklahoma horror was committed by True Believers at the far edge of the "militia'' movement, a paramilitary fringe of the right-to-bear-arms forces in America. Reportedly, the bombers come from a clique of home-grown militants who think the U.S. goverment is conspiring with the United Nations to disarm them and impose a "New World Order.'' They think the tragic 1993 siege in Waco was part of a sinister federal plan to take away private citizens' guns -- a plan that must be resisted and Waco avenged.

Like all cults, this gaggle spreads bizarre talk. One spokesman, janitor Mark Koernke of Michigan, says Los Angeles street gangs are being recruited into a secret police force to disarm Americans. He ends his shortwave radio broadcasts: "God bless the Republic. Death to the New World Order. We shall prevail!''

The first suspect charged in the Oklahoma tragedy, Timothy McVeigh, is an ex-soldier who adores guns and hates government. Acquaintances say he thinks the Army planted a computer chip in his rump after Operation Desert Storm. They say he always carried a pistol, fired wild salvos from automatic weapons, and made a pilgrimage to the scene of the Waco siege. The horrendous fuel-and-fertilizer bomb in Oklahoma City was detonated on the second anniversary of the Waco tragedy, a symbolic date for retribution against the government.

McVeigh's colleagues, brothers James and Terry Nichols, renounced U.S. citizenship, returned their Social Security cards, and spurned drivers licenses and vehicle plates.
McVeigh was caught because he didn't have a license tag on his car -- perhaps another act of rejecting government. He had a large-caliber German pistol in his belt and plenty of cash in his pockets. If he was an unemployed security guard, where did the money come from?

Political scientist John George, an author of Nazis, Communists, Klansmen and Others on the Fringe: Political Extremism in America (Prometheus Books), says of the militia movement: "This kind of group is going to attract the right-wing Christian nationalist, like the Aryan Nation or Aryan Resistance types, the intense white racial nationalists.''

Meanwhile, right-to-bear-arms nuts aren't the only True Believers ready to kill and die in the United States. In Target America: Terrorism in the U.S. Today, Yossef Bodansky, director of the House Task Force on Terrorism and Unconventional Warfare, focuses on foreign-trained Muslim extremists, such as those who blasted the World Trade Center. He says hundreds of them are in America, in secret cells and networks.

"The Islamist terrorists know that their objective will ultimately be realized through Allah's Will,'' Bodansky wrote. "The belief in this inevitability can be compared to the belief in miracles. It is a profound commitment of the individual that is not affected by one's own temporary setbacks or the logic of others.''

The logic of others certainly didn't deter the Oklahom City plotters. They followed their own demented logic.

It's horrifying to realize that the Oklahoma tragedy might be repeated many times in many U.S. cities. America is a wide-open democracy, where all people are free to travel. Explosives, poisons and ingredients for fuel-and-fertilizer bombs are accessible.
The only final ingredient required is the fanatic heart, which sees a massacre of children as an act of bravery. Federal agents will do their utmost to detect such secret murderers in our midst, but the task will be nearly impossible.

Americans can't comprehend True Believers, but it's increasingly clear that we can't escape the nightmares they cause.