13 Greatest Conspiracy Theories in American History

Updated on February 8, 2019
Kosmo profile image

Current events, international affairs, government and American history are a few of the prime interests of Kelley.

Oklahoma City Bombing
Oklahoma City Bombing

It Only Takes Two to Make a Conspiracy

During the short history of the United States, there have been conspiracies to commit crimes, to further a cause, or to gain an advantage. In perhaps the most notable one, John Wilkes Booth and others conspired to assassinate President Abraham Lincoln and members of his cabinet in 1865. Then in 1995, Timothy McVeigh, Terry Nichols, and Michael Fortier conspired to bomb the Alfred P. Murrah Federal Building in Oklahoma City.

Both of these conspiracies led to devastating consequences for the U.S. Therefore, conspiracies are not only theoretical; they actually happen!

The following is a list – in no particular order – of the most impressive conspiracy theories. Perhaps, these stories will convince us that conspiracies do not exist solely in the minds of a few imaginative people.

1. Conspiracy to Assassinate JFK

Perhaps the most investigated conspiracy theory in the U.S. involves the assassination of President John F. Kennedy. The Warren Commission claimed Lee Harvey Oswald was the lone assassin, although many claim Oswald was either “framed” for the murder or conspired with others.

Jack Ruby was a prime suspect in this regard because he murdered Oswald two days after the assassination. Why did Ruby kill Oswald? Was it to keep him from telling the authorities about the conspiracy? Unfortunately, Ruby took this secret to his grave when he died of cancer in January 1967.

Numerous names (including Ruby's) as well as organizations and even entire countries have been implicated in the assassination. Those implicated include: the Italian Mafia, Lyndon B. Johnson, J. Edgar Hoover, Clint Murchison, Fidel Castro, the Federal Bureau of Investigation (FBI), the Central Intelligence Agency (CIA), E. Howard Hunt, and the Soviet Union.

But no solid evidence exists for the complicity of any of the aforementioned. Pop culture begs to differ, however. Oliver Stone’s movie JFK theorizes that the assassination involved nothing less than a coup d’état orchestrated by the federal government of the U.S. Perhaps the best investigative journalism on the assassination and its conspiracy theories is the nine-part TV series The Men Who Killed Kennedy, which implicated a hired French gunman by the name of Lucien Sarti, who allegedly fired the fatal shot from the infamous grassy knoll.

2. "Manchurian Candidate" Assassinations

Many conspiracy theories involve something known as Manchurian Candidate assassins. These unwitting government “sleeper agents" may have murdered prominent people such as Robert F. Kennedy, Martin Luther King Jr., Malcolm X, and John Lennon. They most likely carried out their order at some designated point initiated by the conspirators, after undergoing a period of brainwashing, perhaps in a foreign country.

Theorists argue that government agencies such as the CIA — generally considered a conspiracy itself and often implicated in conspiracy theories — would have more powerful motives than average citizens, and would also be able to create biased commissions to investigate such crimes. Could the CIA have murdered any of these men? You're welcome to do the research.

According to the book and movie titled The Manchurian Candidate, these sleeper agents, once they have committed the assassination, would immediately forget what they had done, or perhaps, commit suicide or immediately be murdered by another government agent, destroying the link to the conspirators.

Waco Siege
Waco Siege

3. Murder of the So-Called "Waco Wackos"

The stand-off at Waco, Texas in April 1993 ended abruptly when self-proclaimed biblical prophet David Koresh, as well as 54 of his Branch Davidian followers and 21 children, were incinerated in a fire that erupted during a military assault initiated by the Bureau of Alcohol, Tobacco, and Firearms (ATF) and the FBI. The Danforth Report, released in July 2000, claimed that the fire was started by the Branch Davidians, but conspiracy theorists assert that the ATF and FBI deliberately started the fire by using incendiary devices during the siege.

These theorists also claim that the Branch Davidians never presented much of a threat, even though they were heavily armed, which isn’t a crime in the U.S. It was also alleged that the Branch Davidians were cooking up methamphetamine, which was never proven.

Did the ATF and FBI conspire to keep the finger of blame firmly pointed at the so-called "Waco Wackos?" Ill-conceived, gung-ho sieges such as the one at Waco and at places like Ruby Ridge incited Timothy McVeigh to commit mass murder in the famous Oklahoma City bombing incident.

4. U.S. Government Orchestrated 9/11 Attacks

The federal government of the United States has been accused of various conspiracies, if not monstrous evils. Perhaps the most incredible conspiracy is the belief that individuals in the U.S. government had advanced knowledge of the 9/11 attacks and deliberately allowed them to happen in order to launch the War on Terrorism, expand the police state, and broaden plans for U.S. global hegemony as envisioned by President George W. Bush's administration.

It is speculated that a new “Pearl Harbor” was needed to actualize such grandiose schemes, the start of which was the invasions of Iraq and Afghanistan. Moreover, some theorists assert that the U.S. government was in league with the 9/11 terrorists and may have set explosive charges, hoping for a kind of controlled demolition to make certain the Twin Towers collapsed. The 9/11 Truth Movement claims to know what “really happened” on that terrifying day in September 2001.

5. Apollo Moon Landings Were Faked

Since the first moon landing in July 1969, conspiracy theorists have claimed that the U.S. government faked the Apollo moon landings because it didn’t have the technology to accomplish the mission. Naysayers also assert that because the U.S. government couldn’t afford such a massive failure during the Cold War with the Soviet Union, the missions were instead shot as Hollywood movies directed by Stanley Kubrick.

Proponents of the moon landings point out that hundreds of thousands of people worked on the Apollo program, so covering up the fakery would have been even more difficult than making the moon landings! A great deal of hardware was left on the moon as well, such as the lunar descent modules. Much of this has been photographed by orbiting probes such as the Lunar Reconnaissance Orbiter. But conspiracies theorists counter by saying that NASA could have faked those photographs as well.

Nevertheless, the TV program Mythbusters in August 2008 subjected many of the hoax-related claims to rigorous scientific methods and eventually labeled all as having been “busted.” Assuming the moon landings took place — which they almost certainly did — they are regarded as the greatest technological achievement in the history of humankind.

USS Eldridge
USS Eldridge

6. Philadelphia Experiment

As the story goes, naval scientists in October 1943 in Philadelphia, PA launched an experiment designed to make a naval destroyer escort, the USS Eldridge, invisible to light and/or radar. These scientists supposedly generated a massive electromagnetic field on the Eldridge, hoping to unify the four forces of nature: gravity, electromagnetism, and the strong and weak nuclear. This Unified Field Theory is a kind of Holy Grail in the world of theoretical physics, though preeminent scientists such as Albert Einstein and Nikola Tesla couldn’t produce a satisfactory model.

But, the experiment went awry when the Eldridge disappeared and teleported some 200 miles away! Apparently, some crew members also vanished and then materialized a short time later as parts of the bulkhead. The U.S. Navy has always denied that such an experiment happened aboard the Eldridge. Interestingly, some U.S. naval ships back then and even today undergo a procedure known as "degaussing" to keep magnetic undersea mines and torpedoes from drawing to the ship.

Was this "degaussing" all that was done to the Eldridge? At any rate, conspiracy theorists claim the experiment did happen, more or less as the events described, and that the U.S. government has covered up the whole story, hoping to keep this fantastic advanced technology to itself.

7. Digital Television Transmission

Some conspiracy theorists claim that the switch to digital TV in the U.S. and other industrialized nations was an attempt by the governments to spy on everyone using miniature cameras and microphones placed in cable boxes and television sets. These techniques, similar to the ones described in George Orwell’s book 1984 would make Orwell’s “Big Brother” concept a reality.

These theorists also think that the digital signals could hold subliminal suggestions so that the entire populace could be controlled and even subverted by governments throughout the world. Perhaps, these techniques are already being used by totalitarian regimes in countries such as North Korea, seemingly the most “controlled” country in the world.

8. Telecommunications Act of 1996

The Telecommunications Act of 1996, the first U.S. congressional bill signed in cyberspace, allows megamergers of media conglomerates to possibly form monster mergers of the media. Conspiracy theorists have warned that this could affect the coverage of wars involving the United States.

One of the companies that expanded into a media conglomerate was General Electric, owner of the National Broadcasting Company (NBC). Also a cause for concern, General Electric has a financial stake in the munitions market, which creates a possible conflict of interest. Theorists claim that the U.S. Congress, which passed the bill with nary a debate, is in league with General Electric and other media conglomerates, in order to maintain control over what the media publishes about the wars in Iraq and Afghanistan. Conspiracy mongers also assert that if these companies control the media, then they control most, if not all, of what the public knows about American incursions into other countries. Of course, they might control considerably more as well!

Road to Area 51
Road to Area 51

9. UFO Conspiracy Theory (Area 51 and Men in Black)

This conspiracy theory may be the granddaddy of them all, stressing the very mythology surrounding UFOs, aliens, clandestine U.S. military bases, and extraterrestrial technology.

Conspiracy theorists allege that the United States government not only has captured and housed extraterrestrials in places such as Area 51, but also conspired with them in the abduction and manipulation of U.S. citizens. One suggestion is that aliens gave the U.S. the transistor in exchange for alien dominance. The enforcers of this covert operation are known as the dreaded Men in Black, who silence those who ask too many questions about alien encounters and abductions. The origin of this unknown and mysterious organization coincides with the Roswell flying saucer epic, which inspired a movie of the same name, as well as episodes of the TV show, The X-Files. This theory also links with the Philadelphia Experiment and the Montauk Project, both of which supposedly conducted experiments in psychological warfare as well as time travel.

10. Secret Organizations Control the U.S.

Seemingly, for hundreds of years, or maybe longer, numerous secret societies or cabals have tried to dominate the world, or at least its central financial system, to deliberately cause inflation and recessions and to manipulate currencies.

For instance, the so-called Zionists are supposedly bent on controlling the world, as are the Illuminati and the Freemasons. These putative clandestine groups may be comprised of the owners of private banks, particularly ones involved with the Federal Reserve System of the United States. Perhaps the Bilderberg Group, a private annual conference comprised of delegates from the United States and European countries, may be engaged in something more than “atlanticism,” as they refer to it. Of course, the secret organizations about which we know absolutely nothing are the ones that may actually be dangerous!

HIV virus
HIV virus

11. Artificial Diseases (AIDS and Ebola)

Some conspiracy proponents think HIV/AIDS was passed from monkeys to humans in the 1930s, while others think the CIA created HIV in the 1980s, a time when HIV/AIDS became a scourge of young people engaging in unprotected sex and people accidentally given tainted blood transfusions. In those days, AIDS was an acutely fatal disease. And, contrary to conspiracy enthusiasts, scientific evidence shows that HIV originated in central Africa in the late 1800s to early 1900s.

Many folks believe that pharmaceutical companies have produced HIV/AIDS and perhaps Ebola as well, in order to reap the rewards of charging exorbitant prices for treatment drugs. Moreover, some conspiracy buffs assert HIV doesn’t cause AIDS; they think poverty or promiscuous sex or illicit drug use - or even the drugs used to treat HIV – are the real causes of AIDS. Astonishingly, contrary to modern science, Thabo Mbeki, former president of South Africa (1999 to 2008), is a promoter of this HIV/AIDS denialism.

Climate change temperature map
Climate change temperature map

12. Climate Change Proponents vs. the Deniers

This conspiracy is a battle of conflicting beliefs – those who think global warming or climate change has been caused by human activity since the dawn of the Industrial Revolution vs. those who think climate change is nothing but a hoax. The former think greenhouse gases need to be greatly reduced, while so-called green technology replaces industries that burn hydrocarbons, thereby reducing greenhouse emissions such as carbon dioxide.

Even though the scientific consensus throughout the world is that the planet has warmed at an alarming rate in recent decades, the climate change deniers or skeptics, want to continue burning fossil fuels until they think the science behind climate change is much more believable and compelling.

Of course, both sides of this environmental issue have much to gain. The creation of green energy, using wind, water, wave or solar, is a growing billion-dollar industry, while proponents of hydrocarbon-burning industries, particularly those generating energy, want to continue operating for decades, if not centuries, reaping massive profits.

Sandy Hook Elementary School
Sandy Hook Elementary School

13. Sandy Hook Mass Shooting

Conspiracy theories have even touched the heart-wrenching mass shooting at Sandy Hook Elementary School in Newton, Connecticut, where on December 14, 2012 a very disturbed young man named Adam Lanza shot and killed 20 young children and six adult staff people.

Conspiracy mongers think it was a staged event designed to provoke gun control legislation by the political left. David Duke, former Ku Klux Klan leader, thinks Zionists killed those kids, while radio show host Alex Jones thinks actors were hired to produce the event. Pundit Rush Limbaugh asserts that Adam Lanza was influenced by the Mayan Calendar event happening at the time of the massacre. Could Lanza have wanted to create an apocalyptic event that would equate with the Mayan phenomena?

Truth is like the sun. You can shut it out for a time, but it ain’t goin’ away

— Elvis Presley


For the average person, the possibility that any one of these conspiracies actually contains an element of truth may seem frightening, amusing, or yawn-inducing. Nevertheless, maybe the wisest course of action is to remain vigilant and trust nothing and nobody, except for the truth, wherever and whenever it can be found.

Questions & Answers

    © 2010 Kelley Marks


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      • Miss Tiff profile image

        Miss Tiff 

        7 years ago from Utah

        This is very interesting. Awesome hub!

      • Kosmo profile imageAUTHOR

        Kelley Marks 

        8 years ago from California

        Thanks for the comment, susankdy. You're right; the truth is usually there to be found - on Fox News or other places. Later!

      • profile image


        8 years ago

        truth is often stranger than fiction and so the seeds of doubt are sown! if something sounds too far fetched it is worth another look, we are blinded by a dumbed down media and even though the truth is easy to find about some controversial subjects - mainstream media shy's away and unless you actively look for information you will not be told by fox


      • Kosmo profile imageAUTHOR

        Kelley Marks 

        8 years ago from California

        Yes, Gypsy Willow, every good conspiracy deserves a movie or two. Later!

      • Gypsy Willow profile image

        Gypsy Willow 

        8 years ago from Lake Tahoe Nevada USA , Wales UK and Taupo New Zealand

        Very interesting hub. These theories have certainly given us some worthy films. Who know what's next?

      • Kosmo profile imageAUTHOR

        Kelley Marks 

        8 years ago from California

        kkalmes, I also have a friend who continually spouts numerous preposterous conspiracy theories until I'm ready to throw a loaded beer can at his head. Ha! Later!

      • profile image


        8 years ago

        Hello Kosmo, great read and while my brother is in town conspiracy theories will continue to be an on-going conversation. Those of us holding desperately onto our sanity aren't as much afraid of the truth as we are afraid of those who promote such preposterous lies.

        thumbs up and awesome because we don't have an excellent rating.

      • John Paterna profile image

        John Paterna 

        8 years ago

        "Just because you're paranoid, doesn't mean they're not out to get you." This should be the motto of conspiracy theorists. Please...

      • Kosmo profile imageAUTHOR

        Kelley Marks 

        9 years ago from California

        You say global disasters to come - OMG! Let's hope they are few and far between, and preferrably not in my lifetime, though I'll do what I can to help in this one. Thanks for recommending my hub, CMCastro. Later!

      • CMCastro profile image

        Christina M. Castro 

        9 years ago from Baltimore,MD USA

        What A Huge amount of interesting information to bring here. A definite READ. I want to recommend this hub to a friend of mine who applies the events of history to the current day crises that this country is going through and how we can prepare for the big global disasters to come. Thanks for your hub.

      • Kosmo profile imageAUTHOR

        Kelley Marks 

        9 years ago from California

        Yes, Immartin, conspiracies are fun to read about, and a few are actually thought-provoking. As usual, thanks for the comment. Later!

      • lmmartin profile image


        9 years ago from Alberta and Florida

        There is nothing more fun that a good conspiracy theory. True/False? Does it matter? Great read. Lynda

      • JayDeck profile image


        9 years ago

        Nice job!



      • Kosmo profile imageAUTHOR

        Kelley Marks 

        9 years ago from California

        There may be an ounce of truth in a few of them, particularly the JFK conspiracy, but that's about it. Most are just too fantastic, if not laughable. Thanks for the comment. Later!

      • rachellrobinson profile image

        Rachel Woodruff 

        9 years ago from Southwest Missouri

        Very informative, just out of curiousity do you believe any of these conspiracies to be true?


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