Plausible deniability

Plausible deniability refers to the denial of blame in loose and informal chains of command where upper rungs quarantine the blame to the lower rungs. In the case that illegal or otherwise disreputable and unpopular activities become public, high-ranking officials may deny any awareness of such act or any connection to the agents used to carry out such act.

In politics and espionage, deniability refers to the ability of a "powerful player" or actor to avoid "blowback" by secretly arranging for an action to be taken on their behalf by a third party—ostensibly unconnected with the major player. In political campaigns, plausible deniability enables candidates to stay "clean" and denounce ads that use unethical approaches or innuendo based on opposition research.

More generally, "plausible deniability" can also apply to any act that leaves little or no evidence of wrongdoing or abuse. Examples of this are the use of electricity, waterboarding or pain-compliance holds as a means of torture or punishment, leaving little or no tangible signs that the abuse ever took place.


Arguably, the key concept of plausible deniability is plausibility. It is fairly easy for a government official to issue a blanket denial of an action, and it is possible to destroy or cover up evidence after the fact, and this might be sufficient to avoid a criminal prosecution, for instance. However, the public might well disbelieve the denial, particularly if there is strong circumstantial evidence, or if the action is believed to be so unlikely that the only possible explanation is that the denial is false.

The concept is even more important in espionage. Intelligence may come from many sources, including human sources. The exposure of information to which only a few people are privileged may directly implicate some of those people in the exposure. For instance, suppose a government official is traveling secretly, and that only one of his aides knows the specific travel plans. Suppose further that the official is assassinated during his travels, and that the circumstances of the assassination (an ambush, perhaps) strongly suggest that the assassin had foreknowledge of the official's travel plans. The only logical conclusion is that the official has been betrayed by his aide. There may be no direct evidence linking the aide to the assassin, but the collaboration can be inferred on the facts alone, thus making the aide's denial implausible.

Plausible deniability in the context of espionage dates back to at least World War II and the Allies' use of ULTRA intelligence, which had secretly broken German Enigma ciphers. For example, if ULTRA revealed a U-boat position, the Allies would not simply send a ship to sink the U-boat. Instead, they might send up a search plane, which would "fortuitously" sight the U-boat, and also ensure that the U-boat saw the search plane. In other cases, the inability to provide plausible deniability forced Allied commanders to avoid taking direct action despite having useful intelligence. In this case, the purpose of going through extra steps or not taking action was to not let the Germans know that their ciphers had been broken.


The expression "plausibly deniable" was first used publicly by Central Intelligence Agency (CIA) director Allen Dulles.

Church Committee

A U.S. Senate committee, the Church Committee, in 1974-1975 conducted an investigation of the intelligence agencies. In the course of the investigation, it was revealed that the CIA, going back to the Kennedy administration, had plotted the assassination of a number of foreign leaders, including Cuba's Fidel Castro. But the president himself, who clearly was in favor of such actions, was not to be directly involved, so that he could deny knowledge of it. This was given the term plausible denial.

Plausible denial involves the creation of power structures and chains of command loose and informal enough to be denied if necessary. The idea was that the CIA (and, later, other bodies) could be given controversial instructions by powerful figures—up to and including the President himself—but that the existence and true source of those instructions could be denied if necessary; if, for example, an operation went disastrously wrong and it was necessary for the administration to disclaim responsibility.

Legislative barriers after the Church Committee

The Hughes-Ryan Act of 1974 put an end to plausible denial by requiring a Presidential finding that each operation is important to national security, and the Intelligence Oversight Act of 1980 required that Congress be notified of all covert operations. But both laws are full of enough vague terms and escape hatches to allow the executive branch to thwart their authors' intentions, as the Iran-contra affair has shown. Indeed, the members of Congress are in a dilemma: when they are informed, they are in no position to stop the action, unless they leak its existence and thereby foreclose the option of covertness.

Media reports on the Church Committee and plausible deniability

The (Church Committee) conceded that to provide the United States with "plausible denial" in the event that the anti-Castro plots were discovered, Presidential authorization might have been subsequently "obscured". (The Church Committee) also declared that, whatever the extent of the knowledge, Presidents Eisenhower, Kennedy and Johnson should bear the "ultimate responsibility" for the actions of their subordinates.

CIA officials deliberately used Aesopian language in talking to the President and others outside the agency. (Richard Helms) testified that he did not want to "embarrass a President" or sit around an official table talking about "killing or murdering." The report found this "circumlocution reprehensible, saying: "Failing to call dirty business by its rightful name may have increased the risk of dirty business being done." The committee also suggested that the system of command and control may have been deliberately ambiguous, to give Presidents a chance for "plausible denial.

What made the responsibility difficult to pin down in retrospect was a sophisticated system of institutionalized vagueness and circumlocution whereby no official - and particularly a President - had to officially endorse questionable activities. Unsavory orders were rarely committed to paper and what record the committee found was shot through with references to "removal," "the magic button and "the resort beyond the last resort." Thus the agency might at times have misread instructions from a high, but it seemed more often to be easing the burden of Presidents who knew there were things they didn't want to know. As former CIA director Richard Helms told the committee: "The difficulty with this kind of thing, as you gentlemen are all painfully aware, is that nobody wants to embarrass a President of the United States.

Iran Contra Affair

In his testimony to the congressional committee studying Iran-Contra affair, Vice Admiral John Poindexter stated: "I made a deliberate decision not to ask the President, so that I could insulate him from the decision and provide some future deniability for the President if it ever leaked out.

Declassified government documents

  • Pentagon papers October 25, 1963 Telegram from the Ambassador in Vietnam Henry Cabot Lodge, Jr. to Special Assistant for National Security Affairs McGeorge Bundy on US Options with Respect to a Possible Coup, mentioning the term plausible denial Alternative link (See Telegram 216)
  • CIA and White House documents on covert political intervention in the 1964 Chilean election declassified. The CIA's Chief of Western Hemisphere Division, J.C. King, recommended that funds for the campaign "be provided in a fashion causing (Eduardo Frei Montalva president of Chile) to infer United States origin of funds and yet permitting plausible denial"
  • Training files of the CIA's covert "Operation PBSUCCESS," for the 1954 coup in Guatemala. According to the National Security Archive: "Among the documents found in the training files of Operation PBSUCCESS and declassified by the Agency is a CIA document titled 'A Study of Assassination.' A how-to guide book in the art of political killing, the 19-page manual offers detailed descriptions of the procedures, instruments, and implementation of assassination." The manual states that to provide plausible denial, "no assassination instructions should ever be written or recorded."


The doctrine had six major flaws:

  • It was an open door to the abuse of authority; it required that the bodies in question could be said to have acted independently, which in the end was tantamount to giving them license to act independently.
  • It rarely worked when invoked; the denials made were rarely plausible and were generally seen through by both the media and the populace.

One aspect of the Watergate crisis is the repeated failure of the doctrine of plausible deniability, which the administration repeatedly attempted to use to stop the scandal affecting President Richard Nixon and his aides.

  • "Plausible denial" only increases the risk of misunderstanding between senior officials and their employees.
  • It only shifts blame, and generally, constructs rather little.
  • If the claim fails, it seriously discredits the political figure invoking it as a defense.
  • If it succeeds, it creates the impression that the government is not in control of the state.

Other examples

Another example of plausible deniability is someone who actively avoids gaining certain knowledge of facts because it benefits that person not to know.

As an example, an attorney may suspect that facts exist which would hurt his case, but decide not to investigate the issue because if the attorney had actual knowledge, the rules of ethics might require him to reveal those facts to the opposing side. Thus his failure to investigate maintains plausible deniability.

Council on Foreign Relations

"...the U.S. government may at times require a certain deniability. Private activities can provide that deniability." --Council on Foreign Relations, an American foreign policy think tank, in the 2003 report, "Finding America’s Voice: A Strategy for Reinvigorating U.S. Public Diplomacy"

Thomas Becket

King Henry II of England is often said to have stated of Archbishop of Canterbury Thomas Becket, "Who will rid me of this meddlesome priest?" Becket was indeed murdered, although the king denied that his plea was to be taken in such a way.

Freenet file sharing

The Freenet file sharing network is another application of the idea. It obfuscates data sources and flows in order to protect operators and users of the network by preventing them (and, by extension, observers such as censors) from knowing where data comes from and where it is stored.

Use in computer networks

In computer networks, deniability often refers to a situation where a person can deny transmitting a file, even when it is proven to come from his computer.

Normally, this is done by setting the computer to relay certain types of broadcasts automatically, in such a way that the original transmitter of a file is indistinguishable from those who are merely relaying it. In this way, the person who first transmitted the file can claim that his computer had merely relayed it from elsewhere, and this claim cannot be disproven without a complete decrypted log of all network connections to and from that person's computer.

Use in cryptography

In cryptography, deniable encryption may be used to describe steganographic techniques, where the very existence of an encrypted file or message is deniable in the sense that an adversary cannot prove that an encrypted message exists.

Some systems take this further, such as MaruTukku and (to a lesser extent) FreeOTFE/TrueCrypt which nest encrypted data. The owner of the encrypted data may reveal one or more keys to decrypt certain information from it, and then deny that more keys exist, a statement which cannot be disproven without knowledge of all encryption keys involved. The existence of "hidden" data within the overtly encrypted data is then deniable in the sense that it cannot be proven to exist.

Deniability in fiction

Deniability is a popular concept in suspense fiction and thrillers:

  • The Mission: Impossible team was deniable, as "Should you or any of your IM force be caught or killed...the Secretary will disavow any knowledge of your actions."
  • In The Godfather: Part II, a Senate committee investigating the activities of Michael Corleone discusses how Corleone always has two buffers between himself and anyone who kills anyone. This provides plausible deniability. If worst came to worst, one link in the chain could disappear.
  • In Clear and Present Danger, military orders are concealed in such a way as to let each commander in turn deny that they ordered a particular mission.
  • A series of novels has been written by Andy McNab about the fictional operative Nick Stone, a deniable "K" operator for British Intelligence.
  • In the video game Metal Gear Solid, it was revealed that the President was unaware of the Metal Gear REX project up until the Shadow Moses Incident.
  • The term was used in the 1996 movie Independence Day when the President asks the Secretary of Defense why he had not been told about the existence of Area 51.
  • The film Tremors 3: Back to Perfection has the main character Burt Gummer mention the concept of plausible deniability regarding the secrecy of the subterranean worms threatening the area.
  • In episode 200 (Stargate SG-1) Carter uses the term to justify the importance her team's participation in augmenting the development of the fictional TV drama Wormhole X-Treme!. The campy but not totally inaccurate drama could be used as a ploy by the Stargate Program's participating governments in the event of unforeseen disclosures of their real activity.
  • The TV show 24 is filled with examples of plausible deniability, with many characters taking morally dubious actions without the consent of their superiors. In particular, Mike Novick and Jack Bauer both risk their careers for President Palmer on numerous occasions.

See also



Further reading

  • Treverton, Gregory F. (1988). Covert Action: The CIA and the Limits of American Intervention in the Postwar World. Palgrave Macmillan. ISBN 1-85043-089-6.
  • Campbell, Bruce B. (2000). Death Squads in Global Perspective : Murder With Deniability. Palgrave Macmillan. ISBN 0-312-21365-4.
  • Shulsky, Abram N; Gary James Schmitt (2002). Silent Warfare: Understanding the World of Intelligence. ISBN 1-57488-345-3. p. 93-94, 130-132

External links

Church Committee links

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