Military Deception: A Handbook

Military tacticians use deception to induce an opponent to act against his own interests, or to refrain from acting when it would be advantageous. The theory and techniques of military deception were detailed this week in a new Army publication for military planners that also implicitly illuminates the role of deception in other contexts.

In one form, deception may increase an adversary’s uncertainty so as to hinder decision-making. In another form, it may decrease uncertainty to encourage the adversary to make a decision that is mistaken.

“Ambiguity-increasing deception is designed to generate confusion and cause mental conflict in the enemy decision maker. Anticipated effects of ambiguity-increasing deception can include a delay to making a specific decision, operational paralysis, or the distribution of enemy forces to locations far away from the intended location of the friendly efforts,” the Army manual said.

Deceptive actions “can cause the target to delay a decision until it is too late to prevent friendly mission success. They can place the target in a dilemma for which no acceptable solution exists. They may even prevent the target from taking any action at all. This type of deception is typically successful with an indecisive decision maker who is known to avoid risk.”

On the other hand, “Ambiguity-decreasing deceptions manipulate and exploit an enemy decision maker’s pre-existing beliefs and bias through the intentional display of observables that reinforce and convince that decision maker that such pre-held beliefs are true. Ambiguity-decreasing deceptions cause the enemy decision maker to be especially certain and very wrong… Planners often have success using these deceptions with strong-minded decision makers who are willing to accept a higher level of risk.”

Even deception has limits and rules, according to the Army. For one thing, the U.S. military is not supposed to deliberately practice deception against the U.S. government or the public.

“Deception activities, including planning efforts, are prohibited from explicitly or implicitly targeting, misleading, or attempting to influence the U.S. Government, U.S. Congress, the U.S. public, or the U.S. news media. Legal staff review all deception activities to eliminate, minimize, or mitigate the possibility that such influence might occur.”

Nor, according to international convention, should instruments of negotiation be abused as tools of deception.

“Flags of truce must not be used surreptitiously to obtain military information or merely to obtain time to affect a retreat or secure reinforcements, or to feign a surrender in order to surprise an enemy.”

See Army Support to Military Deception, Field Manual 3-13.4, 26 February 2019.

By its nature, the effectiveness of military deception depends on secrecy. Specific applications of military deception are addressed in classified publications such as DoD Instruction S-3604.01. The latest (2017) version of Joint Publication 3-13.4 on Military Deception is restricted in distribution.

But the new Army manual is unclassified and was published without restriction.