Where today's political paranoia comes from.

A bad liver killed James Earl Ray last month, but not everyone believes it. No sooner had Martin Luther King Jr.'s assassin died than rumors began spreading that his death was part of a government plot. Not surprising: For 30 years Ray had promoted the theory that the civil rights leader's murder was part of a larger conspiracy.

He wasn't the first to say so. Right after King's death, his aide-de-camp, Ralph Abernathy, hinted at some vast unfathomed plot. White supremacists claimed black militants were responsible. Before Ray was arrested, a group called the Kennedy Assassination Inquiry Committee claimed he was one of the three men in a famous photograph (famous, at least, for Kennedy assassination buffs) of Dallas' Dealey Plaza, where JFK was murdered.

Despite multiple debunkings, these fantasies endure. Most recently, a crackpot named William F. Pepper has convinced King's entire family that the U.S. government, including President Lyndon Johnson, was responsible for his death.

Why do we love conspiracy theories so much? Many people refuse to accept James Earl Ray's guilt (or Lee Harvey Oswald's in JFK's assassination) because they can't accept that one insignificant lowlife could topple a hero and alter history. More generally, conspiracism (as Middle East scholar Daniel Pipes calls it) flourishes during turbulent times--revolutions in particular--when long-established orders seem imperiled by uncontrollable events, endangered powers imagine secret plots to undermine them, and the dispossessed worry about persecution. With their grand designs in which everything has its place, conspiracists seek to impose a reassuring order on the randomness of history. As the late historian Richard Hofstadter noted in his famous essay "The Paranoid Style in American Politics," "[T]hey regard a 'vast' or 'gigantic' conspiracy as the motive force in historical events. History is a conspiracy."

The histories conspiracists concoct are convoluted--counterhistories full of strange codes and logic through which factual history can be glimpsed as in a fun-house mirror. Conspiracy theorists adopt the trappings of scholarship, touting irrelevant titles and credentials. They burrow into the arcana of their topics and inundate potential acolytes with a barrage of pedantic details. Rather than build a case from evidence, conspiracists deny the available evidence, maintaining that appearances deceive. Rather than admit to inconvenient facts, they dismiss them as lies, making their own theories irrefutable. (King conspiracism neatly exemplifies these classic traits.)

Modern conspiracism is almost a thousand years old. Pipes, in a book called Conspiracy: How the Paranoid Style Flourishes and Where It Comes From, pinpoints the Crusades of the 11^th century--the wars waged by Europe's Christians on the Muslims who controlled Palestine--as its first mass outbreak. To legitimize their attacks, Crusaders demonized their Muslim foes--not hard to do, since the Muslims had a competing empire and religion of vast size and power. But Europe's Jews, too, had to be converted or killed. How to justify the eradication of a weak and numerically insignificant group? The Crusaders convinced themselves the Jews were a secret cabal with insidious powers, out to destroy Christendom.

Besides this anti-Semitism, Pipes identifies a second, related strain in Western conspiracist thought: fear of secret societies. This variety focused on small groups (other than Jews) whose rituals seemed mysterious and whose beliefs seemed threatening to Christianity. Masons--professional stonecutters--were the earliest targets. Since medieval times, masons had devised confidential phrases and handshakes to recognize fellow craftsmen and protect their trade secrets from outsiders. During the Enlightenment, their guilds became clubs for discussing the new liberal ideas of deism and toleration (and also came to include nonstonecutters as members). Religious authorities feared that, within their lodges, the Masons, too, were plotting Christianity's doom.

Pipes contends these two strains of conspiracism co-existed and intermingled over the years, giving rise to various fantasies of global schemes. Typically, these fantasies have centered on such staples as the Bavarian Illuminati (a Masonlike order founded in 1776), the Rothschilds (a Jewish banking family of the 18^th century) and, later, the Council on Foreign Relations (a bunch of foreign-policy wonks who meet on East 68^th Street).

Though European in origin, conspiracism has thrived in the United States. But where aristocratic Europe feared closed-door cabals of powerful men, democratic America's suspicions focused on its own government. The American Revolution, most scholars now agree, was itself an outgrowth of conspiracism: The colonists rebelled because they imagined a systematic plot by the monarchy to deprive them of their liberties. King George III and his ministers were actually just blundering their way through the tricky business of running a trans-Atlantic empire, but suspicious Americans viewed each restriction of their rights--the Stamp Act, the Tea Act, and so on--as part of a scheme to reduce them to slavery. And so the Revolution.

Democratization fostered more conspiracy-mongering. By the 1820s and '30s, most states were allowing all white men to vote (before that, they had to own land), and President Andrew Jackson was leading his famous "war" on the national bank. In this climate popular hostility was trained against powerful private interests and gave new life to anti-Masonry as a political movement. (Masonic lodges were often made up of leading figures in the community.) The Anti-Mason Party was formally born in Rochester, N.Y., in 1826, when a Mason who had quit the organization was murdered, and it became a robust third party in the 1832 elections. Masonry came to be seen, as Hofstadter put it, as "a standing conspiracy against republican government."