Plausible deniability is, at root, credible (plausible) ability to deny a fact or allegation, or to deny previous knowledge of a fact. The term most often refers to the denial of blame in (formal or informal) chains of command, where upper rungs quarantine the blame to the lower rungs, and the lower rungs are often inaccessible, meaning confirming responsibility for the action is nearly impossible. 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 acts.
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 advertisements 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 electric shock, waterboarding or pain-compliance holds as a means of torture or punishment, leaving few or no tangible signs that the abuse ever took place.
Plausible deniability is a legal concept. It refers to lack of evidence proving an allegation. Standards of proof vary in civil and criminal cases. In civil cases, the standard of proof is "preponderance of the evidence" whereas in a criminal matter, the standard is "beyond a reasonable doubt." If your opponent lacks incontrovertible proof (evidence) of their allegation, you can "plausibly deny" the allegation even though it may be true.
Contents |
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 these situations, the purpose of forbearance or superfluous action prevented the Germans from realizing their ciphers had been broken.
The expression "plausibly deniable" was first used publicly by Central Intelligence Agency (CIA) director Allen Dulles.[1] The idea, on the other hand, is considerably older. For example, in the 19th century, Charles Babbage described the importance of having "a few simply honest men" on a committee who could be temporarily eliminated when "a peculiarly delicate question arises" so that one of them could "declare truly, if necessary, that he never was present at any meeting at which even a questionable course had been proposed."[2]
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.[3]
Non-attribution to the United States for covert operations was the original and principal purpose of the so-called doctrine of "plausible denial." Evidence before the Committee clearly demonstrates that this concept, designed to protect the United States and its operatives from the consequences of disclosures, has been expanded to mask decisions of the president and his senior staff members.
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.
The Hughes-Ryan Act of 1974 sought to 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.[5]
| “ | 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.[6] | ” |
| “ | CIA officials deliberately used Aesopian language[7] 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"[8] 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."[9] | ” |
| “ | 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"[10] 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."[11] | ” |
In his testimony to the congressional committee studying the 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."[12]
The doctrine had six major flaws:
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.
"...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"
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.
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 dis-proven without a complete decrypted log of all network connections to and from that person's computer.
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.
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. In this case the system is said to be Fully Undetectable, FUD.
Some systems take this further, such as MaruTukku, FreeOTFE and (to a much lesser extent) 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.
The Underhanded C contest is an annual programming contest involving the creation of carefully crafted defects, which have to be both very hard to find and plausibly deniable as mistakes once found.