A piece by Clifford D. May from the Foundation for the Defense of Democracies that appeared in the Washington Times contained the following statement:

The paradox of deterrence is that the stronger we are, the less likely that our adversaries will provoke a conflict with us. By contrast, if we appear weak or wobbly, those who despise us will be emboldened to take their best shots.

This is a rather facile understanding of deterrence. Strength does not necessarily increase deterrence. Deterrence is a very difficult thing to achieve in international affairs because it is intimately tied to the level of analysis, information, perceptions, and the security dilemma.

The level of analysis matters greatly. For example, most of the work on nuclear deterrence, treats states as unitary rational actors. That is a state makes decisions doing costs-benefit analysis and chooses the option with the most gain (or least loss). That simplifying assumption appears to have worked well for theories of nuclear deterrence. Nuclear deterrence rests on the idea that having a viable second strike capability on both sides. It ensures that weapons will not be used, because the first use is guaranteed to result in a counter-strike. Given the destructive power of strategic nuclear weapons, the result is the destruction of both sides. For this reason, the so-called nuclear triad is very important. Possessing intercontinental ballistic missiles, bombers, and sea launched ballistic missiles ensures that a first strike could not knock out a state’s entire arsenal, and enough will survive for the counter strike. For nuclear deterrence to work, all that is required is rationality and information, the more perfect the better. Better information reduces the likelihood of miscalculation. Even so, during the Cuban Missile Crisis there was almost a nuclear weapon used by a Russian submarine under attack by US destroyers enforcing the quarantine of Cuba. Use of a nuclear weapon might in turn have set off an escalatory spiral. (Russia’s deployment of IRBMs in Cuba was to address an imbalance of forces because at the time Russia was struggling with its ICBM program and thought that the US advantage in interceptor fighters, made thee Russian bomber fleet insufficient to deter a US first strike. The Russians wanted to bring more of the continental United States under nuclear threat.

Deterrence has been less effective in conventional arms because it is tied to perceptions. The state as a unitary rational actor seems not to hold well. For example, whether offense or defense in war has the advantage has a bearing on the calculus of decision makers. Decision makers may “fight the last war” and misunderstand how technology has changed the nature of war. At a more tactical level, information problems abound. How good is the intelligence? After all, military decision makers disguise movements and behave in rationally irrational ways–for example, marching the army over the mountain and not down the road which would be faster, because it enhances surprise. Incentives to dissemble abound.

States themselves may not be unitary actors. Without strong civilian control of the military, actions may be undertaken that are detrimental to the state for parochial military reasons. When states leverage irregular war strategies such as proxies and militias, or in the case of Iran, parallel security institutions, the idea that a state will behave as a unitary actor are imperiled.

Deterrence rests upon credible threat. This is what May is getting to, but strength doesn’t necessarily make a threat credible. There are many ways of making threats more credible. I’ll refer you to Schelling’s classic analysis of threat for a more detailed discussion, including how weakness can actually enhance the credibility of threat. One of the key ways of making a threat more credible is to remove options for concessions thereby shrinking the policy space. Another key way is to use unpredictability for advantage. When a state behaves unpredictably, the state may be able to drive a harder bargain than were its true preferences known. Think of Nixon’s approach during the Vietnam War, when trying to extract concessions from North Vietnam, he cultivated the idea that he was irrational.

Strength can actually be a detriment to successful deterrence, because it can result in the security dilemma. A state feels threatened, so it increases its military capability, thereby increasing the costs associated with an attack, however, the military buildup makes the other state more insecure, resulting in an arms race, or a temptation to attack in order to preempt the state from getting stronger.

Finally there is the issue of crazy states. Yehezkel Dror in his Crazy States: A Counterconventional Strategic Problem, laid out a typology of ways states have preferences that are in his terminology “counter reasonable”. An extreme example: millenarianism produces preferences that are “counter reasonable” because willingness to destroy one’s self to destroy an enemy is counter reasonable, violating the basic principle of self preservation.

Thus, strength does not automatically increase the level of deterrence. Credible threats can be made even from positions of weakness. Perceptions of threat may activate a security dilemma–for example, it is possible that Iran embarked on a covert nuclear weapons program as a way of deterring the United States from pursuing regime change, ditto North Korea–and finally, the states themselves may not behave rationally. They may not do cost-benefit analyses and act as a utility maximizer, a prerequisite for analytical tools for understanding state behavior like game theory that has worked so well in developing doctrines of nuclear deterrence.