Counterforce

In nuclear strategy, a counterforce target is one that has a military value, such as a launch silo for intercontinental ballistic missiles, an airbase at which nuclear-armed bombers are stationed, a homeport for ballistic missile submarines, or a command and control installation. The intent of a counterforce strategy (i.e., attacking counterforce targets with nuclear weapons) is to disarm an adversary by destroying its nuclear weapons before they can be launched, thereby minimizing the impact of a retaliatory second strike. A counterforce target is distinguished from a countervalue target, which includes an adversary's population, economic, or political resources. In other words, a counterforce strike is against an adversary's military while a countervalue strike is against an adversary's cities.

Theory
In nuclear warfare, enemy targets are divided into two types: counterforce and countervalue. A counterforce target is an element of the military infrastructure, usually either specific weapons or the bases which support them. A counterforce strike is an attack which targets these elements whilst leaving the civilian infrastructure – the countervalue targets – as undamaged as possible. Countervalue refers to the targeting of an opponent's cities and civilian populations.

An ideal counterforce attack would kill no civilians. Military attacks are prone to causing collateral damage however, and this is especially true when nuclear weapons are employed. In nuclear terms many military targets are located in proximity to civilian centres, and a major counterforce strike employing even relatively small nuclear warheads against a nation would certainly inflict numerous civilian casualties. Further, the requirement to use ground burst strikes to destroy hardened targets would produce enormously more fallout than the air bursts used to strike countervalue targets; introducing the possibility that a counterforce strike would cause more civilian casualties—over a medium-term view—than a countervalue strike.

Counterforce weapons could be seen to provide more credible deterrence in future conflict by providing options for leaders. One of those options considered by the Soviet Union in the 1970s is basing missiles in orbit.

Cold War
Counterforce is a type of attack which was originally proposed during the Cold War.

Both sides in the Cold War took steps to protect at least some of their nuclear forces from counter-force attacks. At one point the US kept B-52 Stratofortress bombers permanently in flight; these would remain operational after any counter-force strike. Other bombers were kept ready for launch on short notice, allowing them to escape their bases before intercontinental ballistic missiles could destroy them. The deployment of nuclear weapons on ballistic missile submarines changed this equation considerably – submarines launching from positions off the coast would likely destroy airfields before bombers could launch, reducing their ability to survive an attack. Submarines themselves, however, are largely immune from counter-force strikes and both sides fielded many such weapons during the Cold War.

A counter-force exchange was one scenario mooted for a possible limited nuclear war. The concept was that one side might launch a counter-force strike against the other; the victim would recognize the limited nature of the attack and respond in kind, leaving the military capability of both sides largely destroyed. The war might then come to an end because both sides would recognize that any further action would lead to attacks on the civilian population from the remaining nuclear forces – a counter-value strike. Critics of this idea claimed that since even a counter-force strike would kill millions of civilians it is unlikely that escalation to a full-scale counter-value war could be prevented.

MIRVed land-based ICBMs are considered destabilizing because they tend to put a premium on striking first. If, for example, 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. In this case, the side that strikes first 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. For such an attack to be successful, the warheads would have to strike their targets prior to the enemy launching a counter-attack. It is because of this that this type of weapon was banned under the START II agreement.

Counterforce disarming first-strike weapons

 * R-36M (SS-18 Satan). Deployed in 1976, this counterforce MIRV ICBM had single (20 Mt) or 10 MIRV (550-750 kt each) warheads, CEP 250 m. Targeted against Minuteman III silos as well as CONUS command, control, and communications facilities. Has sufficient throw weight to carry up to 10 RVs and 40 penaids. Still in service.
 * RSD-10 (SS-20 Saber). Deployed in 1978, this counterforce MIRV IRBM could hide behind the Urals in Asian Russia, and launch its highly accurate 3 warhead payload (150 kt each, with a 150 m CEP) against NATO command, control, and communications installations, bunkers, air fields, air defense sites, and nuclear facilities in Europe. Extremely short flight time ensured NATO would be unable to respond prior to weapon impact. Triggered development and deployment of the Pershing II by NATO in 1983.
 * Peacekeeper (MX Missile). Deployed in 1986, this missile boasted 10 MIRV warheads each with a 300 kt yield, CEP 120 m. Decommissioned.
 * Pershing II. Deployed in 1983, this single warhead IRBM boasted 50 m CEP with active radar terminal guidance. Short, 7-minute flight-time, variable yield warhead of 5-50 kt, and range of 1,800 km, allowed this weapon to strike command, control, and communications installations, bunkers, air fields, air defense sites, and ICBM silos in the European part of the Soviet Union with scarcely any warning. Decommissioned.
 * RT-23 Molodets (SS-24 Scalpel). Deployed in 1987, this MIRV ICBM carried 10 warheads, each with 300-550 kt yield and a CEP of 150–250 m.
 * Trident II. Deployed in 1990, this intercontinental-range SLBM carries 8 RVs with CEP of 80–120 m and yield of 100/475 kt. Main purpose is second-strike countervalue retaliation, but the excellent CEP and much shorter flight-time due to submarine launch makes it a first-strike weapon. However, that any nuclear power would be willing to place its nuclear submarines close to enemy shores during times of strategic tension is highly questionable. Has sufficient throw weight to deploy up to 14 warheads, but 8 are deployed in current practice.