Strategic Chess: The Logic of Deterrence

The Logic of Deterrence

Considering that the objective of deterrence is to prevent, or rather reduce the probability of enemy military attacks, two actors can be identified:

• the aggressor – albeit potential;
• the deterrer – who seeks to prevent or dissuade the aggressor from launching the attack.

Attempting to outline all potential interactions between the aggressor and the deterrer, assessing every possible variable, in order to explain how deterrence works would be excessively time-consuming and perhaps impossible to fully encompass.

Instead, although inevitably reductive for deterrence theory, this article goes over the logical workings of deterrence in a simple and schematic manner. It thus considers:

1. The Aggressor's Strategic Analysis
2. The Deterrer's Strategic Analysis
3. The Elements of Deterrence at Stake
4. Subsequent Interactions and Strategic Adjustments

1. The Aggressor's Strategic Analysis

The likelihood of the aggressor carrying out his attack stems from his risk/benefit calculus, which depends on 4 factors:

1. “His valuation of his war objectives;
2. the cost which he expects to suffer as a result of various possible responses by the deterrer;
3. the probability of various responses, including ‘no response’ [which represents the credibility of the threats posed by the deterrer]; and
4. the probability of winning the objectives with each possible response” (Snyder, 1960, p.167).

• For the simplifying purposes of this outline, the deterrence response refers to the entire deterrence strategy.

Hence, when the aggressor assesses the probability of success, it takes into account not only the initial threat but also considers all possible responses, including defensive actions that may need to be countered. In short, this calculation is the overall probability of winning the war, defined as achieving the initial objectives (Snyder,1961, p.12).

An important, delicate point is to raise here: the credibility of the deterrer is what binds the aggressor’s risk calculus to the cost-benefit calculus of the deterrer.

2. The Deterrer's Strategic Analysis

Similar to the aggressor, who evaluates the risks and benefits of launching an attack, the deterrer also conducts a cost-benefit analysis in order to develop an effective strategy aimed at thwarting the potential gains of the aggressor.

Assuming the rationality of the deterrer, his response to the aggression will be determined by the following factors:

1. “His valuation of the territorial objective and of the other intangible gains (e.g., moral satisfaction) which he associates with a given response;
2. the estimated costs of fighting;
3. the probability of successfully holding the territorial objective; and
4. the change in the probability of future enemy attacks on other objectives which would follow from various responses”(Snyder, 1960, p.167).

Both the deterrer and the aggressor will select the policy option that minimises the expectation of cost and maximises the expectation of gain.

3. The Elements of Deterrence at Stake

Here, all elements of deterrence, i.e., capability, communication, credibility, and uncertainty, play a key role.

In particular, due to both a lack of total information and the possible irrationality of an actor, uncertainty can make the aggressor and deterrer estimates completely wrong.

Therefore, in the mutual cost-benefit assessment crucial for adapting their strategies, both the deterrer and the aggressor engage in a series of interactions to mitigate and minimise uncertainty.

Such interactions serve to search

“for intelligence, for options, even for clarification of the state’s own interests and intentions as well as those of the other side” (Sigal,1979, p.571).

4. Interactions and Strategy Adjustments

A “spiral of ‘guesses about the other’s guesses’” begins (Snyder, 1960, p.168).

• The credibility of the deterrer potential responses depends on how the aggressor perceives the deterrer's risk assessment - that is, the deterrer's evaluation of the costs and benefits of each response. Additionally, it depends on the aggressor's judgment of the rationality of the deterrer.
• The aggressor can estimate how the deterrer will perceive his (the aggressor’s) gains and losses calculation after every possible response and rely on this to make a judgement on the manner and likelihood of a response.
• The deterrer, in turn, “evaluates the effectiveness of his deterrent posture by attempting to guess the values of the four factors in the aggressor’s risk calculus” (Snyder, 1960, p.168).
• In order to understand his own credibility from the aggressor’s point of view, the deterrer tries to assess how the aggressor estimated his (the deterrer’s) cost-benefit calculation.
• Through this spiral, the deterrer is able to estimate whether the aggressor expects to benefit or suffer from the attack, and, relying on this assessment, he determines the likelihood of aggression, adjusting his strategy accordingly (Snyder, 1960, p.168).

Furthermore, once the attack is initiated, the deterrer will choose the response that minimises their own costs or maximises their gains, rendering previous calculations about deterrence irrelevant to the immediate situation.

Lastly, the aggressor lacks full knowledge of the deterrer's estimates of costs and benefits. Even the deterrer cannot predict in advance how he will perceive his own gains and losses, and thus, his actual response during an attack. Additionally, the aggressor cannot be certain the deterrer will act rationally according to his cost-benefit analysis.

Due to these uncertainties, “the aggressor's estimate of [the deterrer's] credibility cannot be precise” (Snyder, 1961, p.14) and states “can deal with this problem only by taking a pragmatic standpoint and by accepting this uncertainty and ambiguity as something immanent in the system” (Tunander, 1989, p.357).

📌 Key Takeaways

Just as in chess, where players must anticipate their opponent's moves while carefully planning their own, in the real world aggressors and deterrers must do the same when planning their strategy.

Yet, despite efforts to foresee every possible outcome, uncertainty inevitably clouds the battlefield. In the realm of strategic ambiguity, both aggressors and deterrers must deal with imperfect information and the unpredictability and irrationality of human behaviour.

While deterrence theory provides a framework for understanding and managing conflict, it also underscores the inherent limitations of strategic foresight.

In the pursuit of peace, one must recognise that the true test of strategic mastery lies not only in our ability to anticipate moves but also in our capacity to forge a path toward mutual understanding and cooperation on the global chessboard of geopolitics.

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