Deterrence theory is nuclear weapon utilization strategy first used during the Cold War. It was derived from the basis that it is all but impossible to physically protect a country from a large-scale nuclear attack; it is much more effective to prevent the attact entirely. Deterrence theory uses a country's nuclear arsenal to deter an enemy from attacking.
There are five assumptions of deterrence theory:
- Decision making regarding nuclear weapons must be rational: all actors must behave in a way that maximizes their interests.
- Decision making is highly centralized: each actor has top-level control over nuclear weapons.
- Each actor must make similar calculations about what can be gained or lost through use of nuclear weapons.
- Each actor must believe their opponent possesses nuclear weapons to inhibit hostile action, not undertake it.
- Each actor must believe there is a chance their opponent will use nuclear weapons if provoked (where their credibility is a function of nuclear capability and national resolve).
Two modes of deterrence
The assured destruction mode of deterrence is where each actor says they will completely destroy the other if attacked. In this mode, nuclear weapons are only used for deterrence, and their use will escalate into total ruination of both actors. AD attacks are aimed at countervalue targets, such as population centers and places of government. Targetting these places will ensure that as many people are killed as possible, thus reducing the will and capacity to attack again.
The damage limitation mode of deterrence is where both actors target their opponents nuclear and conventional weapons capability (counterforce targeting). An attack under this mode will not result in the total destruction of either or both sides, rather it will result in limited nuclear warfare.
Problems with deterrence theory
As in any discipline, if any of the assumptions of deterrence theory prove false, the expected outcome of the theory is no longer valid. Most political scientists agree that assured destruction works better with assumptions 1 through 4, but damage limitation works better with assumption 5.
- Rational decision making would be difficult during the course of nuclear war. This is not a problem with AD, because all weapons are launched at once, and there is no further decision making.
- Tactical nuclear weapons require decentralization. For DL to work, commanders on the ground would have to have some control over the use of tactical nuclear weapons.
- Warfare would be chaotic; pressures could compel one side to use nuclear weapons and not the other.
- If an actor sees his opponent building up an arsenal, he can not tell whether the opponent is preparing for war or preparing in case deterrence breaks down.
- Annihilation for any transgression is not credible. If the threat of attack is no longer credible, AD deterrence breaks down.
There are also other destabilizing factors unrelated to which method is used. For example, rogue states and terrorist organizations are not limited to being rational actors, so deterrence theory breaks down against these groups. Missile defence systems also destabalize deterrence, because they remove the fear of retaliation; which could lead to a possibility of a first strike attack for a small provocation. Multiple independently targetable reentry vehicle missiles (MIRVed missiles) are also destabalizing, because they make it difficult for an actor to calculate the capability of his opponent.