I admit it, I'm highly skeptical of conspiracies like the 9/11 Truthers, Flat Earthers, etc...

The way I see it? "these things always come out in the end, see for example the Gulf of Tonkin incident, or Hitler's various false flag operations that fooled no one. So conspiracies don't work and a worldview based on their generalized, or at least frequent, existence is problematic."

Edit: Please note that this is asking about cases that successfully deceived the public for more than 25 years. A number of suggestions were made that would qualify, except that the mess blew up before 25 years were up. So, by definition, nothing that happened before 1994 is in scope as of 2019. And even if it predated 1994, there is the criteria that exposure took at least 25 years.

There is a big flaw in my reasoning. If you discount conspiracy theories just based on the ones you know of that did not work, that doesn't account for the ones that did because no one found out. And if they worked because no one knew of them so they can't be used to prove that conspiracies do exist and do affect our governments.

So, what are some known examples of conspiracies that worked from the point of view of the perpetrators?

  • Needs to involve a nation state, possibly in collusion with a commercial entity. Not just a commercial entity: one knows not to expect honesty from tobacco companies for example.

  • It needs to have affected national policy and a large number of people, preferably negatively, in that state. I.e. shady deals to secure oil fields in a far away land isn't necessarily something that voters have historically cared much about.

  • However, starting a war between your country and a foreign state under false pretenses certainly counts.

  • The people being fooled, citizens of that state, would need to have felt strongly negative if they had found out. i.e. no "harmless little white lies at election time". Again, that brings in a notion of active harm to the citizens at large.

  • The conspiracy needs to be secret, have fooled, or at least been disbelieved, by the general public. Going back to tobacco companies, no one really believed their lies. And that also rules out the Gulf of Tonkin as it has always been strongly disputed. Global warming is also out as whatever side a government takes, either "wrongly disbelieving it" or "acting too strongly on unwarranted assumptions", the public is already well aware this a major policy issue.

  • The state in question needs to be, or at least pretend to be, a democracy with a free press. It's all to easy to come up with cover ups in totalitarian states. And if there's no press, it's not obvious how people would hear of the misdeeds.

How do we judge success?:

The perpetrators need to have benefited from it. But since we need to know about it, I'll arbitrarily say that, if the facts only came out after a generation (25 years), then the con was successful as the people doing it have likely retired and/or statute of limitations have kicked in.

Note that this 25 year limit also aims this question at historical events, rather than current events where the facts are still up for debate.

And, it needs to be now generally accepted by historians that it was actually a cover up/conspiracy.

Feel free to edit and/or ask clarifications. I tried to frame it to include only the typologies found in some of the big common conspiracy theories involving governments found nowadays like inside job 9/11, Flat Earth, faked moon landings, vaccine scares, etc... I specifically want to rule out things like say a car company for example successfully covering up exploding gas tanks on its own - a government needs to be in the lead. Ditto government positions that were not in the best interests of its citizens but were already widely known at the time - secrecy is key in a conspiracy. While certainly negative, things like the Hanford nuclear plant's release of radioactive material isn't really what I have in mind as it's not an attempt to affect national policy.

  • Comments are not for extended discussion; this conversation has been moved to chat. Commented Nov 6, 2019 at 10:48
  • One fundamental problem with this question is that truly successful conspiracies would never be uncovered. And there may be a thresholding effect - conspiracies that successfully last X years may have a high probability of succeeding forever, because the people with knowledge die, the people who care about the matter die, etc.
    – tbrookside
    Commented Nov 6, 2019 at 16:07
  • 1
    25 years might not be enough to limit it to historical events. Many outside observers think or at least suspect that Paul Kagame, the current president of Rwanda, ordered the assassination of Juvénal Habyarimana in 1994 (the event which precipitated the Rwandan genocide). The facts are still up for debate. Commented Nov 6, 2019 at 17:13
  • @JohnColeman the 25 years is not so much about limiting to historical events as it is a metric of sorts: if the conspiracy lasted that long then it "succeeded" at manipulating government/sentiment during its lifetime, even if it comes to light later. as a side effect, it does force people to go back to history and avoid focussing overmuch on current events. also, suspicion by itself doesn't mean the conspiracy "fails" - if Kagame had a hand in that murder, then, yes, he got away with it. but... Rwanda is also out of scope for not being a full-on democracy with an open press in 1994, Commented Nov 6, 2019 at 20:34
  • 1
    Annii di Piombo? The "theory"-part is somehow self-defeating with +25 years:: The theory is out soon, where is the "blown up"-angle? Consider Reichstag-fire. Immediately people said: "Nazis did it!!" Then Lubbe was made scape-goat for a long time and dispute raged for decades. Now, very recently, we see that SA is really prime perpetrator. Does that count? Millions said it before. // Isn't it really about "real conspiracy" uncovered only +25 years later –– no theories in the meantime? // Or "Theories" turned out "real"? Commented Nov 6, 2019 at 21:35

3 Answers 3


The "Noto Servizio" or "Anello" in Italy should qualify.

The "Noto Servizio" was an Italian secret organization made up of former officers, entrepreneurs, industrialists, subjects of the political and economic world, and organized crime, founded towards the end of World War II by fascist war-criminal Mario Roatta, although Wikipedia doesn't know much…) and survived, with various transformations, at least until the early nineties.

The association for several years had close contacts with the secret services, the leaders of the armed forces and Italian politics, influencing the life of all Italian citizens through their interference in the political events of the country, including economics, terrorism, politics and even attempted coup d'etat.

Most the high members of the state knew of the existence of the association, but it was so powerful and influential that no one who had made contact with it ever dared to talk about it to the public, even after the association had ceased to exist.

Many were the people who benefited from the existence of the association, in addition to entrepreneurs and politicians, even the members of organized crime, in particular the Sicilian mafia of Cosa Nostra, were greatly enriched by lending their "services" to the association in exchange of money, favors and concessions.

Recent investigation showed that it was used essentially for anti-communist political conditioning operations and actions that aimed to oppose elements and parties of the left, disinformation campaigns and direct interventions such as kidnappings (like Aldo Moro or Ciro Cirillo), elimination of the adversaries and in many economic and criminal scandals of the Republic.

The discovery of the existence of this secret structure came to light in 1996-98, thanks to the work of an historian that, on behalf of a Milanese judge who was investigating into extreme right-wing terrorism of the '70s, discovered a series of documents in an abandoned archive in Rome written by an infiltrated journalist, linked to the Ufficio Affari Riservati (lit. Office for reserved affair) that was suspected of having provided support and / or coverage to those responsible for some of the most serious acts of terrorism that occurred in those years.

for me it is a valid conspiracy because:

  • It lasted well over 25 years
  • It was initially discovered after roughly 5 years from it's disappearance but its existence was confirmed by investigations concluded much later.
  • It concerned the entire Italian state, from the simple citizen unaware of the manipulations to the politician forced to bend to the will of this force
  • It involved entrepreneurs and industrialists who used contacts to their advantage, not only to obtain contracts or concessions, but also to weaken the strikes and workers' protests of those years
  • The state and politicians made propaganda to their citizens on the fight against terrorism, both on the right and on the left, and on the fight against the mafia, when in reality they used them continuously

During the various recent investigations on the alleged relations between Italian secret services and organized crime it turns out that the association is more or less involved with almost all the major events of the post-war years to the '90s that occurred in Italy, including the massacres and terrorist attacks. The common Italian population of the time (and in part still today) attribute these negative events to various components active in those years, such as the Brigate Rosse, the NAR or the mafia of Cosa Nostra, but no one suspected that something larger existed, inextricably linked to the state, which maneuvered these forces more or less directly.

Wikipedia entry (in Italian)

A more complete explanation from the birth to various involvements (in Italian)

  • 1
    first upvote from me. I am finding it impossible to find any substantial info on this case in English, but otherwise it is a good fit overall. Commented Nov 6, 2019 at 20:35
  • 2
    I am a complete ignorant about this, but it sounds more like a criminal organisation rather than a government conspiracy. In a conspiracy, a small group of people actively mislead the population and hides the truth. Where's the conspiracy?
    – Bregalad
    Commented Nov 7, 2019 at 8:20
  • @Bregalad I believe that during the 70s and 80s and the Red Brigades scare there was some questions and rumors about government death squads, or at least extra-legal attempts to throttle Communist support. that would be a government conspiracy, even if the Mafia was involved, as long as it was done secretly and off the books. now I am unsure that's what the answer is talking about since the information is so scant, at least in English. something of what I am talking about, with no idea about its veracity: theguardian.com/world/2000/jun/24/terrorism Commented Nov 7, 2019 at 20:51
  • Gladio, see en.wikipedia.org/wiki/Operation_Gladio looks like a contender for a successful conspiracy - see Vincenzo Vinciguerra - , if it turns out that its sleeper cells committed crimes against Communist sympathizers, rather than just remaining dormant and passive. It's not proven that that was actually the case, though I wouldn't at all be surprised if it had. Commented Nov 7, 2019 at 22:39
  • 1
    @italian-philosopher The "Anni di piombo" (Years of Lead) in Italy were a period full of plots and conspiracies, in which the state used every means at its disposal to counter the rise of communist ideas, even using people of the extreme far-right and organized crime to pursue its own objective. By contrasting the extreme right and the extreme left in a climate of constant battle, the state maintained its power over the population, effectively weakening both factions. Galdio was just one of these plots, the P2 Masonic lodge was another one that comes to mind.
    – Viralk
    Commented Nov 8, 2019 at 8:37

Assuming the verdict in the ongoing trial turns out "guilty", the 1MDB scandal should qualify. I'm not an expert on the scandal, but it meets all your criteria:

  1. It involved the Prime Minister of Malaysia.
  2. It involved a state-funded agency, 1MDB.
  3. Because it involves corruption, the Malaysian people would undoubtedly have felt negatively about it if they knew.
  4. The government denied it, such that it was several years before the opposition (which made 1MDB a central part of their campaign) won the next general election.
  5. The first section of the Wikipedia article indicates there were newspapers investigating the scandal.
  6. If the allegations are true, then the perpetrators certainly benefited from it (having siphoned several billion MYR).

Of course, this all assumes the allegations are true.

  • 3
    it's less than 10 years old. the whole point is to look at cases where a successful coverup lasted at least 25 years. I'll edit the question to make that more obvious. but yes, otherwise, it would qualify. large public malfeasance and expectation that they would get away with it. Commented Nov 5, 2019 at 23:13

The Antarctic "Ozone Hole crisis"

As still noted in Wikipedia as of this writing (Nov. 5 2019, Guy Fawkes Day) the expected time required for recovery of the Ozone hole remains decades into the future, until late this century, specifically 2060–2075:

The Antarctic ozone hole is expected to continue for decades. Ozone concentrations in the lower stratosphere over Antarctica will increase by 5–10 percent by 2020 and return to pre-1980 levels by about 2060–2075. This is 10–25 years later than predicted in earlier assessments, because of revised estimates of atmospheric concentrations of ozone-depleting substances, including a larger predicted future usage in developing countries. Another factor that may prolong ozone depletion is the drawdown of nitrogen oxides from above the stratosphere due to changing wind patterns.[94] A gradual trend toward "healing" was reported in 2016.

Note in particular, from above:

Ozone concentrations in the lower stratosphere over Antarctica will increase by 5–10 percent by 2020


This [2060-75] is 10–25 years later than predicted in earlier assessments ....

The official scientific explanation for the ozone hole is that recovery is delayed because developing countries haven't yet completely stopped use and production of CFC's. All CFC theories for a man-made cause of the ozone hole require that it be stable or shrinking very slowly for decades to come. The facts plainly contradict that.

Yet the latest report from NASA on Oct. 21 2019 reports that the ozone hole size is the smallest on record since it was discovered in 1982. That is to say it has in fact fully recovered, which is not possible under any explanation posited for the ozone hole being caused by CFC's:

Abnormal weather patterns in the upper atmosphere over Antarctica dramatically limited ozone depletion in September and October, resulting in the smallest ozone hole observed since 1982, NASA and NOAA scientists reported today.

As noted lower in the article, the ozone hole is affected dramatically by local weather in September and October each year, when it peaks in an annual cycle. Levels of man made chlorofluorocarbons in the atmosphere remain well above levels that predict - according to the theory - stable at best ozone hole size; yet the hole has shrunk none the less.

Comments have asked "Where is the conspiracy?"

The conspiracy is that thee were always scientists who disputed the CFC cause for the ozone hole, yet these were shouted down by environmentalists on the basis of "better safe than sorry". The Montreal Protocol was established as an international agreement to reduce CFXC's. Once air conditioner manufacturers realized how much money was to be made in replacing every A/C in the world 10 to 40 years ahead of schedule - they signed on gleefully and most of the world simply lost interest.

  • 10
    How is there a conspiracy theory? Commented Nov 5, 2019 at 21:51
  • 9
    Are you saying CFCs are not causing the ozone hole at all and this is generally accepted by a large proportion of the scientific community? Correct if I am wrong, but what I see here is scientific uncertainty and a lack of obvious motive. As well, you would have to indicate who started this conspiracy, why and why everyone went along with it, it certainly has been inconvenient for all the industrial users of CFCs and the manufacturers. Commented Nov 5, 2019 at 21:54
  • 7
    @PieterGeerkens yes, but even IF that was the case, how do you make it into a willful conspiracy? science occasionally gets things wrong - see for example the past reluctance to accept bacteria as the cause of most ulcers. the fact that it suited the providers of not-bacteria-caused ulcer medication hardly means that the scientific community knowingly covered up the root cause of ulcers - it just went against accepted wisdom. Commented Nov 5, 2019 at 21:59
  • 12
    There's an ongoing and international scientific effort to monitor the sources of CFCs and their impact on the ozone layer. To hand-wave that away is just mind-boggling... Commented Nov 5, 2019 at 23:25
  • 15
    I hope we're being pranked here, because this post checks all of the boxes for conspiracy theory itself.
    – Spencer
    Commented Nov 6, 2019 at 0:36

Not the answer you're looking for? Browse other questions tagged or ask your own question.