A truTV Conspiracies interview with Kathryn S. Olmsted, University of California history professor and author of Real Enemies: Conspiracy Theories and American Democracy, World War I to 9/11, just released in paperback.

In Real Enemies, you concentrate on conspiracy theories of the 20th century. Is there anything peculiar about theories from that era compared to others?

Throughout the 20th century, the U.S. government got bigger and more secretive and powerful. In some cases, it actually began to carry out real conspiracies, especially beginning in the Cold War. As a result, Americans came to wonder: if the government is responsible for these real conspiracies, what else has it done that we don’t know about yet?

The book focuses on the United States. Is America more susceptible to conspiracy theories than other countries?

People in all lands and eras believe in conspiracy theories, but the most popular theories can provide a window into the fears of a particular culture. In 18th- and 19th-century America, people worried that their country was uniquely open—and vulnerable—to foreign, “un-American” conspirators. Frightened Americans targeted Catholics, Masons, Mormons and Jews because these native groups were allegedly guided by the instructions of an alien power. In the 20th century, though, more and more Americans came to see their own government as the sinister force that was subverting their republic.

What was the first time in history that a large number of people became convinced of a conspiracy?

Well, the Trojans discovered there were a lot of Greeks conspiring inside that horse.

How would you explain the public’s fascination with conspiracies?

Psychologists say that the people who tend to believe in conspiracy theories are those who feel most threatened by random events. And as societies become bigger and more impersonal, random and meaningless events increase in frequency. In conspiracy theories, someone is always in charge. Even if this person is evil, the belief that someone planned these events can be oddly comforting.

And conspiracy theories can be entertaining mysteries. People love to think that they can be the ones to solve a historical crime.

Where do you draw the line between a healthy distrust of power and paranoia?

On the one hand, conspiracy theories can be useful in forcing government officials to release more information. In that sense, they can help strengthen democracy. But on the other hand, these theories can cause people to become so alienated that they drop out of the political process. This profound lack of trust can make it difficult for a democratic government to function at all.