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15 Presidential Mysteries That Were Never Solved

Updated: Aug. 04, 2021

Not even presidents of the United States are immune to suspicious circumstances or curious conundrums.

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President Harry S. Truman, Washington, USA
Herbert K White/AP/Shutterstock

Did President Truman cover-up a UFO?

From Congressional records, we know John Quincy Adams believed the earth was hollow. If only there were Congressional records to shed light on whether Harry S. Truman, our 33rd President, believed that outer-space-aliens landed in Roswell, New Mexico…or whether he ordered a cover-up of all evidence of such landing. What we do know is that in July 1947, the military actually announced that a UFO had crash-landed in the Roswell desert, and the next day, they said, sorry, nope, that didn’t actually happen. Somewhere in between, President Harry S. Truman is believed to have turned up in Roswell to examine the crash site. The question remains, did our 33rd president orchestrate what may be American history’s most massive UFO cover-up? Roswell isn’t the only place conspiracy theorists believe aliens may have landed—find out all the U.S. government secrets about Area 51, another suspected alien hotspot.

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What was really on the missing portion of the Watergate tapes?

Between February 1971 and July 1973, President Richard M. Nixon secretly recorded 3,700 hours of conversations he wasn’t supposed to be recording, including those that became the basis of the Watergate scandal. When the existence of the tapes became public knowledge during that scandal, it was quickly discovered that 18 and a half minutes of a conversation between Nixon and his chief of staff, Bob Haldeman, was nothing more than audio feedback. Multiple attempts over the years to recover what’s come to be known as the “missing” audio have proved fruitless, and to this day, no one knows for sure what Nixon and Halderman were discussing. Based on the audio that’s not missing, there’s every chance the missing audio would have been extremely prejudicial.

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Various 1923, No Location - President Warren G. And Mrs. Florence Harding
Nara Archives/Shutterstock

Warren G. Harding: Poisoned…by Mrs. Harding?

On August 2, 1923, President Warren G. Harding dropped dead as his wife, Florence, read him an article from The Saturday Evening Post. A serial philanderer, Harding had been warned by doctors his ticker might not stand up to all the excitement, but Florence’s refusal to allow an autopsy gave rise to speculation she had poisoned him. Another theory, based on a review of Harding’s deteriorating health in the days leading to his death, is that our 29th president, at the age of 57, died of plain old ordinary heart failure.

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Various June 1920 - President Woodrow Wilson, seated at desk with his wife, Edith Bolling Galt, standing at his side

Who was running our country between October 1919 and January 1920?

In October 1919, President Woodrow Wilson suffered a stroke that was kept secret for another four months. Even then, no official statement was made as to Wilson’s health or his ability to discharge his duties and powers as president. After a while, people became suspicious that our 28th president wasn’t “all there” and that his wife, Edith, might actually be running the country. In fact, she most likely was—and the first woman to do so—but this was kept a secret from the American public until years Woodrow’s death. Edith wasn’t our only impressive First Lady, as these 43 facts about presidential spouses attest.

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Historical Collection 32 James Buchanan 15th President of the United States 1791 - 1868

Was James Buchanan the first gay president?

James Buchanan is the only bachelor president in U.S. history. While he had his niece act as First Lady, his long-term “roommate” was a man. To some, this begs the question: was Buchanan, sworn into office in 1857, our first gay president? To others, there’s no question. That includes the historian Jim Loewen, who maintains Buchanan was not only gay but that his sexual orientation wasn’t even a secret back in the day. There’s no first-person evidence to prove this since Buchanan’s personal correspondence was destroyed upon his death (at Buchanan’s own request). Here are some more (confirmed) presidential firsts you might not know.

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Sen. John F. Kennedy, Washington, USA - 1960

John F. Kennedy: The case of the missing brain

John F. Kennedy’s assassination continues to be shrouded in secrecy and unanswered questions and one reason we may never definitively know what really happened is that sometime after JFK’s autopsy, his brain went missing. Consequently, any questions that came up as a result of the investigation run by the House Assassination Committee, whose questions might have required investigators to take a new look at JFK’s brain, are effectively unanswerable. Forever. So who took JFK’s brain. And why? And don’t forget these 12 other unanswered questions about the day he died.

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Franklin D. Roosevelt: Yes, a stroke, but why?

No one disputes that on April 12, 1945, President Franklin D. Roosevelt died of a stroke. What’s mysterious is whether his stroke was the result of coronary artery disease…or metastatic cancer that had spread to his brain. Lots of evidence points to cancer, including his general frailty and weight loss at the end of his life, and a spot on his forehead that some medical professionals identify by sight as melanoma, and which disappeared from photos of our 32nd president after 1940. But the answers continue to elude us to this day.

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Various Between 1870 and 1881 - James A. Garfield. Assassinated President of the United States.

James A. Garfield: Death by bullet…or by malpractice?

James A. Garfield is thought to have been the second of four presidents to have been assassinated by gunshot. But the passage of time has gradually shed light on what really killed Garfield, who was lucid after the July 2, 1881 shooting and lived for another 79 days. Turns out it probably wasn’t the bullet, but the gross ineptitude of the doctor attending to him. Unable to locate the bullet, the doctor probed Garfield’s wound several times a day with unsterilized fingers and makeshift devices, until Garfield succumbed to sepsis. An autopsy confirmed the bullet alone would not have killed him.

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Art (Portraits) - various
The Art Archive/Shutterstock

Grover Cleveland: Gone fishing?

Grover Cleveland, our 22nd and 24th president, didn’t die in office, but his whereabouts in June 1893 were a bit of a mystery. Officially, Cleveland had “gone fishing” for a few days when in truth, he was having oral surgery to remove a tumor from his palate. Later that summer, the story leaked, but Cleveland denied it. In 1908, after Cleveland died of a heart attack, Cleveland’s doctor confirmed the surgery but remained vague about the diagnosis. In 1980, a re-examination of the tissue removed from Cleveland’s palate revealed he did, in fact, have a non-fatal form of cancer.

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President Abraham Lincoln

Lincoln’s assassination: A Confederate conspiracy?

HIstorians and the general public are in agreement that Abraham Lincoln was fatally shot by the actor, John Wilkes Booth, who was embroiled in a conspiracy with a small handful of anarchists to murder the 16th president. But since that fateful night, people have questioned whether Booth was capable of orchestrating such an enormous crime. Given the Union’s recent victory over the Confederacy, suspicions turned to Confederate leaders including Jefferson Davis as well as the pro-slavery secret society, the Knights of the Golden Circle. Could Booth have been the original “patsy”? It appears we may never know.

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Historical Collection 2 William Henry Harrison (1773-1841) 9th President of the United States (1841-1841) He Died On His 32nd Day in Office 1841

William Henry Harrison: Talked himself to death?

Poor William Henry Harrison. Fate was unkind to our ninth president, who only spent a mere 31 days in office before he died on April 4, 1841. But history’s been even more unkind, blaming Harrison’s death on pneumonia he’s thought to have contracted while delivering his two-hour inauguration speech—the longest in history—outside in the freezing rain. While “catching a chill” actually can lead to pneumonia, new evidence points to typhus, which is spread through sewage-contaminated water, and which he likely contracted by drinking the water at the White House. Find out the presidential trivia that people get wrong.

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History Thomas Jefferson (1743-1826) 3rd president of the USA. Engraving after portrait by Desnoyers
Universal History Archive/UIG/Shutterstock

Did Thomas Jefferson father children with one of his slaves?

Although Thomas Jefferson authored the Declaration of Independence, whose “all men are created equal” language catalyzed the anti-slavery movement, it’s no secret Jefferson owned slaves. What became an enduring mystery—starting as soon as Jefferson took office in 1801—is whether Jefferson fathered as many as six children with his slave, Sally Hemings, beginning in 1787 (five years after the death of Jefferson’s wife, Martha). In the late 20th century, DNA testing revealed a “high probability” that Jefferson fathered all of Heming’s children, as acknowledged by the Thomas Jefferson Foundation, although some think the children were fathered by Jefferson’s younger brother Randolph. Find out more facts you never knew about U.S. presidents.

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Art (Portraits) - various
The Art Archive/Shutterstock

Chester Arthur: Was he actually Canadian?

Vermont claims our 21st president, Chester Arthur, as its own, but then…so does Canada. “The focus on his place of birth became an issue in the 1880 presidential campaign when Arthur was tapped to be the running mate for Garfield,” according to Boston.com. “According to historical accounts, Republican bosses wanted him to provide proof of his birthplace, but he never did.”

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Bill Clinton campaigning in Waco, Texas, USA - 28 Aug 1992
Mark Reinstein/Shutterstock

Did Bill Clinton have his enemies offed?

Since the 1990s, rumors have circulated President Bill Clinton and his wife, Hillary, are responsible for the deaths of a number of people who were known to possess information against the Clintons’ interests. These include James McDougal, Vince Foster, and Seth Rich. The fact-checkers at Snopes makes a strong, logical argument to prove the negative (i.e., The trouble is that proving a negative is virtually impossible.) So while for those who disbelieve the rumors, there is no mystery, for those who persist in perpetuating the rumors, the mystery will never be solved unless and until the rumors are proven true.

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Historical Collection 138 Zachary Taylor American Soldier and Statesman President 1849 - 1850 - He Died in Office 1784 - 1850

Zachary Taylor: Death by cherries?

Zachary Talyor is another president whose untimely death while in office in 1850 has been the subject of gentle mocking. It’s said he died after “overindulging” in an “imprudent” quantity of cherries with milk. But the strangeness of the circumstances has also given rise to the theory that his death was a homicide via arsenic poisoning. In 1991, that theory was officially put to bed, however, when Taylor’s body was exhumed and tested negative for arsenic. It’s still not known exactly what caused the death of our 12th president. Conspiracy theorists will want to read on to find out about 16 of the strangest unsolved mysteries of all time.