First Strike - Destabilizing Role of Land-based MIRVed ICBMs

Destabilizing Role of Land-based MIRVed ICBMs

MIRVed land-based ICBMs are generally considered suitable for a first strike or a counterforce strike, due to:

1. Their high accuracy, compared to submarine-launched ballistic missiles which are less accurate, and more prone to defects;
2. Their fast response time, compared to bombers which are considered too slow;
3. Their ability to carry multiple warheads at once, useful for destroying a whole missile field with one missile.

Unlike a decapitation strike or a countervalue strike, a counterforce strike might result in a potentially more constrained retaliation. Though the Minuteman III of the mid-1960s was MIRVed with 3 warheads, heavily MIRVed vehicles threatened to upset the balance; these included the SS-18 Satan which was deployed in 1976, and was considered to threaten Minuteman III silos, which led some neoconservatives to conclude a Soviet first strike was being prepared for. This led to the development of the aforementioned Pershing II, the Trident I and Trident II, as well as the MX missile, and the B-1 Lancer.

MIRVed land-based ICBMs are considered destabilizing because they tend to put a premium on striking first. When a missile is MIRVed, it is able to carry many warheads (3 to 14 in existing U.S. missiles; 3 to 12 in existing Soviet missiles) and deliver them to separate targets. If it is assumed that each side has 100 missiles, with 5 warheads each, and further that each side has a 95 percent chance of neutralizing the opponent's missiles in their silos by firing 2 warheads at each silo, then the attacking side can reduce the enemy ICBM force from 100 missiles to about 5 by firing 40 missiles with 200 warheads, and keeping the rest of 60 missiles in reserve. As such, this type of weapon was intended to be banned under the START II agreement, however the START II agreement was never activated, and neither Russia nor the USA has adhered to the agreement.