President Donald Trump quite famously loves conspiracy theories. He’s won the hearts of many Americans (and infuriated plenty of others) by questioning Barack Obama’s U.S. citizenship, calling climate change a hoax, and making “fake news” the word of the year in 2017. But Trump isn’t the only president who has bought into conspiracy theories over the years.
Read on to discover the most surprising conspiracy theories that presidents actually promoted.
1. Thomas Jefferson bought into a dubious theory about preventing colds
- 3rd president of the United States
Presidents are only human. Even those early presidents who, like Thomas Jefferson, loom large as near-mythical figures in the American imagination. But even Jefferson bought into some pretty strange conspiracy theories about health and wellness. (Admittedly, that was not a tough thing to do in the days when mercury was still widely used as a medicine.)
Like many of us, Thomas Jefferson would go to great lengths to ensure that he didn’t catch a cold or the flu. Jefferson became convinced that if he soaked his feet in a bucket of cold water each day, he would never get a cold. Interestingly enough, the Thomas Jefferson Encyclopedia reports that Jefferson proudly attributed his lack of common colds to his “habit of bathing my feet in cold water every morning, for sixty years past.”
Next: This president believed the earth might be hollow.
2. John Quincy Adams believed the Earth was hollow
- 6th president of the United States
Smithsonian Magazine reports that John Quincy Adams once approved an expedition to the center of the earth. The reason why? He actually believed a theory that proclaimed the Earth to be hollow. Smithsonian Magazine notes that even at the time, most people considered the idea laughable. But Adams still believed it, and wanted Congress to fund an expedition proposed by Army officer John Cleves Symmes, Jr.
Nonetheless, his unpopularity as president meant that he only served a single term. And his successor, Andrew Jackson, killed the funding for the expedition. Nonetheless, Adams had a passionate interest in the natural world. That passion led him to pursue the founding of a national observatory, and to ensure that the money from James Smithson’s estate went toward the founding of the Smithsonian Institution.
Next: This president thought the earth was flat.
3. Andrew Jackson believed the Earth was flat
- 7th president of the United States
CNN reports that according to his private secretary Nicholas Trist, Andrew Jackson reportedly told a family member that he didn’t believe the Earth was round. Likewise, The Plain Dealer reports that Andrew Jackson really believed the world was flat.
Contrary to what you might expect, the idea that the world was flat was never actually a widespread belief, according to Newsweek. Ancient Greeks and Romans accepted the knowledge of a spherical earth. All major medieval scholars regarded the Earth’s roundness as an established fact. Only 19th century writers misrepresented church fathers as believing in a flat Earth, perhaps influencing Jackson’s views on the matter.
Next: This president bought into conspiracy theories about Catholic immigrants.
4. Millard Fillmore thought Catholic immigrants wanted to overthrow the government
- 13th president of the United States
Millard Fillmore bought into one of the most ridiculous conspiracy theories of all, becoming a member of the Know Nothing Party. According to The Smithsonian Magazine, members “wanted to restore their vision of what America should look like with temperance, Protestantism, self-reliance, with American nationality and work ethic enshrined as the nation’s highest values.”
The New Republic reports that the party believed “that Catholic immigrants owed their allegiance, not to the burgeoning American government, but to the Pope, whose autocratic ruling style was antithetical to American democratic values.” Fillmore and others wanted to “trample” any Catholic influence on American politics or society.
Next: This president believed prejudiced conspiracy theories about Jews.
5. Ulysses S. Grant thought Jews were organizing a black market for cotton
- 18th president of the United States
History reports that Ulysses S. Grant expelled Jewish people from Tennessee, Kentucky, and Mississippi based on his belief that they were organizing a black market for cotton trade between the north and the south. At the time, Grant wasn’t yet president. Instead, he was serving as commander of the military’s administrative department of Tennessee (which consisted of Tennessee, Kentucky, and Mississippi). President Abraham Lincoln permitted limited trade in southern cotton, but tasked Grant with shutting down black market trade.
As History puts it, Grant was “swayed by the commonly held prejudice that Jews were largely responsible for war profiteerin.” So be blamed the district’s Jewish community for organizing the illegal trade in black-market cotton. Grant prohibited the issuing of trade licenses to Jews within the Tennessee district. And it required them to leave the district within 24 hours or risk imprisonment.
Next: This president feared something in the White House.
6. Benjamin Harrison thought the White House light switches could electrocute him
- 23rd president of the United States
As Gizmodo reports, Benjamin Harrison became the first president to install electric lighting at the White House. Yet he never touched the light switches himself “for fear of being electrocuted.” Harrison and his wife reportedly slept with the lights on some nights instead of touching the light switches themselves.
It sounds a little ridiculous to fear light switches. But electric lighting was relatively new at the time — hence Harrison’s fear that the light switches could seriously harm him. As Gizmodo notes, “This was a reasonable fear, given how crude household electric wiring could be at the time.” Harrison had his domestic staff operate the light switches for him.
Next: This president had some weird theories about his health.
7. Calvin Coolidge had a strange method for improving his health
- 30th president of the United States
Many of us struggle to figure out which health tips we should follow and which we should ignore. You might assume that that’s a modern problem, brought about by the information overload associated with the internet. Yet due to a lack of modern medical knowledge, plenty of presidents bought into strange conspiracy theories about human health.
HowStuffWorks reports that Calvin Coolidge subscribed to a strange theory about improving his health. “Apparently, he enjoyed having petroleum jelly rubbed all over his head every morning, while he enjoyed his breakfast in bed.” Nobody knows exactly where Coolidge got the idea that that would improve his health. But he definitely considered the theory valid.
Next: This president went on a treasure-hunting expedition to an island where treasure still hasn’t been found.
8. Franklin D. Roosevelt went treasure-hunting on Oak Island
- 32nd president of the United States
We all love the idea of buried treasure, and sometimes wish we could go search for it ourselves. At least one president of the United States also shared that impulse. The Daily Beast reports that Roosevelt was one of the early adopters of the theory that Captain Kidd left his treasure on Oak Island, a small piece of land off the coast of Nova Scotia. You may remember it as the topic of the popular History show The Curse of Oak Island, which details the still-ongoing search for treasure on the island.
Roosevelt first became intrigued by the idea of a buried treasure on the island, which was famed for its sinkhole, called “the money pit.” In 1909, Roosevelt sailed to Oak Island and helped finance the “Camp Kidd” headquarters for a treasure-hunting expedition. He later wrote to a friend, “I wish much I could have gone up the coast this summer and visited Oak Island and seen the work you are doing — for I shall always be interested in that romantic spot.”
Next: This president believed numerous conspiracy theories.
9 Richard Nixon was paranoid about almost everything
- 37th president of the United States
History News Network plainly characterizes Richard Nixon as a conspiracy theorist. The publication explains, “The government has systematically declassified hundreds of hours of White House tapes recorded on a voice-activated system that President Nixon had the Secret Service install in the oval office. They reveal a textbook example of what historian Richard Hofstadter called ‘The Paranoid Style in American Politics.'”
Nixon targeted three groups of Americans with his conspiracy theories: Jews, intellectuals, and Ivy Leaguers. Nixon believed that “There were too many Ivy League men, too many intellectuals, too many radicals, too many Jews.” Mashable reports that Nixon “was always suspicious of the potential plots swirling around him.” And “The press is the enemy,” Politico reports Nixon would tell his staff.
Next: This president wanted to deport John Lennon.
10. Nixon thought everyone on the left was ‘out to get him,’ including John Lennon
Clearly, Nixon bought into conspiracy theories about many different groups of people. But As The Toronto Star explains one of Nixon’s most specific fears, the president “believed everyone on the left was out to get him.” One bizarre manifestation of that belief? Nixon also thought it was necessary to deport John Lennon.
According to The Toronto Star, “Lennon had spoken out in support of radical causes and ergo was wiretapped, followed and, finally, threatened with deportation since he wasn’t a U.S. citizen.” NPR reports that for much of 1972 and 1973, Lennon “was under an order to leave the country within 60 days.” It wasn’t until after Watergate, and after Nixon left office, that the immigration service under Gerald Ford’s administration finally agreed to grant Lennon his green card.
Next: This president thought he saw a UFO.
11. Jimmy Carter thought he saw a UFO
- 39th president of the United States
Jimmy Carter believed that he saw a UFO. As Politico reports, Carter asserted that he had witnessed an unidentified flying object in 1969. Carter said that the object was self-luminous and about as bright as a full moon. He also said that about 10 people saw it, and that it remained visible for around 10 minutes. When he shared the experience, he was serving as Georgia’s governor. And he went on to become the president only a few years afterward.
And even though he said he didn’t think it was extraterrestrial in origin, Carter still reported the incident to the International UFO Bureau in Oklahoma City, Oklahoma. In fact, Carter maintained that “his knowledge of physics — as an Annapolis graduate, he had been assigned to the U.S. Navy’s nuclear submarine program — ruled out the possibility that he had witnessed an alien spacecraft.”
Next: This president believed conspiracy theories about a major medical crisis.
12. Ronald Reagan didn’t think AIDS was a real problem
- 40th president of the United States
Ronald Reagan didn’t believe that AIDS was a serious problem. His position on the matter didn’t exactly amount to a conspiracy theory, especially because he made a point of failing to talk about the crisis in public. But his position was just as harmful as a conspiracy theory would have been.
Gizmodo reports that Reagan became “eager to sweep the AIDS crisis under the rug,” opening the door for an “HIV denialist movement.” Snopes reports that a variety of rumors about AIDS arose. Those conspiracy theories claimed that the disease was “an out-of-control germ warfare virus that escaped from its handlers,” “spread by specific ethnic groups,” “put in K-Y Jelly by the Centers of Disease Control to eliminate homosexuals,” “developed by the CIA,” or even “developed by the Russians.”
Next: This president believed a strange theory about marijuana.
13. Reagan also thought marijuana would create as much brain damage as a hydrogen bomb
AIDS isn’t the only topic on which Ronald Reagan bought into some theories that were a little far removed from the facts. And we’re not just talking about how Reagan allowed an astrologer to guide his schedule in the Oval Office.
Though many presidents have smoked marijuana — or have at least been suspected of dabbling in it — Reagan stood firmly against it. Reagan also bought into a pretty demonstrably false theory about marijuana, once saying, “I now have absolute proof that smoking even one marijuana cigarette is equal in brain damage to being on Bikini Island during an H-bomb blast.”
Next: Donald Trump has espoused lots of conspiracy theories.
14. Donald Trump has promoted many conspiracy theories
- 45th president of the United States
Of all of our presidents, Donald Trump has been one of the most open about believing or at least promoting conspiracy theories. That habit began a long time before Trump even considered running for office. But it certainly continued into his time in the Oval Office.
Mother Jones reports that Donald Trump has “made the paranoid style of American politics go mainstream” by floating countless conspiracy theories. Trump has called climate change a hoax. He’s expressed doubt about the veracity of reports of Russian meddling in the presidential election. Trump also claims that Muslims celebrated on 9/11. Plus, he said that Barack Obama wiretapped his home. And he has promoted claims of a link between vaccines and autism.
Next: This may be the strangest of the conspiracy theories that Donald Trump promoted.
15. Donald Trump believed that Ted Cruz’s dad was involved in JFK’s assassination
But one of the most interesting examples of Donald Trump’s propensity for promoting conspiracy theories? Trump floated a theory that Ted Cruz’s father was involved in the assassination of John F. Kennedy. FiveThirtyEight reports that most Americans believe at least a few JFK conspiracy theories. So it comes as no surprise that Donald Trump has had something to say on the topic.
As ABC explains, Trump promoted the theory that Ted Cruz’s dad was involved in John F. Kennedy’s assassination, despite any real evidence to support the assertion. Yet as CNN notes, “It’s not important whether he believes all the conspiracy theories he helps churn up and push into the mainstream. What’s important is that by doing so he benefits politically.”
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