As the 20th century began, conspiracy was simply how Brazilian politics got done. Paranoia was everywhere, and often warranted. Secret plotting and military coups were routine across the political spectrum. And by the end of the Cold War, citizens in Brazil’s young democracy had inherited a world of deep-seated suspicions, and would have to look back on a dizzying set of contradictory narratives to understand their own history.

In 1930, one of these putsches propelled a man named Getúlio Vargas to the presidency. Then conspiracies, both real and fake, helped lead the country to dictatorship. In 1935, a right-leaning newspaper published a story—entirely false—reporting that communists were planning an uprising that would eliminate “all non-communist officials.” But then leftists, worried about a fascist turn in the Vargas government, did attempt a real rebellion. It was quickly crushed, but not before Vargas used it to justify the consolidation of dictatorial powers.

Two years later, right-wing forces came up with another fake conspiracy, one that would stoke paranoia for decades. Plano Cohen, or the “Cohen Plan,” was, supposedly, a dastardly Jewish-Communist plot to overthrow the government. It was a forgery, drawn up by the fascist General Olímpio Mourão Filho. But it was presented—and covered by the press—as if it were real, and Vargas used the invented crisis as justification to carry out a new coup and launch a full-fledged dictatorship.

What happened over the next three decades provided even more fuel for Brazil’s culture of conspiracism. In 1962, with democracy restored, officials in Washington worried about President João “Jango” Goulart, a liberal reformer: In a recorded conversation, President John F. Kennedy and United States Ambassador Lincoln Gordon agreed they should discreetly inform the Brazilian military that it could take action “against the left,” if needed. The U.S. stepped up covert operations in Brazil, and Kennedy sent the military attaché Vernon Walters into the country. Brazil’s right-wing forces began to spread the accusation that a communist coup was brewing, even as they plotted themselves. When the U.S.-backed coup started on March 31, 1964, the charge on Rio de Janeiro was led by Mourão Filho—the same man who created Plano Cohen three decades earlier. The general that took over as the first “president” in the resulting dictatorship, Humberto Castelo Branco, had been roommates with Walters—JFK’s military man in Rio—back in the 1940s.

It’s no wonder that Brazil is fertile ground for conspiracy theory. What you just read is the true story of how Brazilian power and political might whipsawed back and forth from democracy to dictatorship in the 20th century; or at least it’s the closest thing we have to the truth. But this account emerged only after years of research, after historians pored over thousands of declassified documents; for a long time, anyone guessing at the real truth would have been, by definition, a conspiracy theorist. That’s because powerful actors had indeed conspired behind closed doors—to smear the left, to align Brasília with Washington, to lie to the public—but without all the evidence, the best citizens could do was theorize about their nature.

These episodes also point to a recurring pattern, and a dominant theme, in the politics of Brazilian conspiracy: The forces seeking to upend the social hierarchy in this stratified society usually lose, and those who win often weaponize conspiracy theory to justify their own movements. As a result, conspiracy theories in Brazil usually end up reinforcing the powers that be. Latin America’s largest country now offers a chilling reminder of the ways that rumor-mongering and disinformation can shore up elite power and subvert democracy.

For the past 100 years, by far the most powerful of Brazilian conspiracy theories is the tale of an international communist plot to destroy the nation. “The red menace is the most powerful threat used to scare Brazilians—both in the past and today. It is a story that many of us thought would go away after the end of the 20th century, but it has come back in a big way,” Rodrigo Patto Sá Motta, a historian and the author of On Guard Against the Red Menace: Anti-Communism in Brazil, 1917-1964, told me. “Without a doubt, conspiracy theories have helped authoritarians, time and time again, in Brazil.”