Editing Mutual assured destruction (section)

===MIRVs===
{{main|Multiple independently targetable reentry vehicle}}
{{Unreferenced Section|date=August 2013}}
[[File:Peacekeeper RV vehicles.jpg|thumb|right|175px|A time exposure of seven [[multiple independently targetable re-entry vehicle|MIRVs]] from [[Peacekeeper missile]] passing through clouds]]

==== MIRVs as counter against ABM ====
The [[multiple independently targetable re-entry vehicle]] (MIRV) was another weapons system designed specifically to aid with the MAD nuclear deterrence doctrine. With a MIRV payload, one [[ICBM]] could hold many separate warheads. MIRVs were first created by the United States in order to counterbalance the Soviet [[A-35 anti-ballistic missile system]]s around Moscow. Since each defensive missile could be counted on to destroy only one offensive missile, making each offensive missile have, for example, three warheads (as with early MIRV systems) meant that three times as many defensive missiles were needed for each offensive missile. This made defending against missile attacks more costly and difficult. One of the largest US MIRVed missiles, the [[LGM-118A Peacekeeper]], could hold up to 10 warheads, each with a yield of around {{convert|300|ktonTNT|PJ|lk=in}}—all together, an explosive payload equivalent to 230 [[Little Boy|Hiroshima-type]] bombs. The multiple warheads made defense untenable with the available technology, leaving the threat of retaliatory attack as the only viable defensive option. MIRVed land-based ICBMs tend to put a premium on striking first.<!--For example, assume 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. 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. --> The [[START II]] agreement was proposed to ban this type of weapon, but never entered into force.

In the event of a Soviet conventional attack on [[Western Europe]], [[NATO]] planned to use [[tactical nuclear weapons]]. The Soviet Union countered this threat by issuing a statement that any use of nuclear weapons (tactical or otherwise) against Soviet forces would be grounds for a full-scale Soviet retaliatory strike ([[massive retaliation]]). Thus it was generally assumed that any combat in Europe would end with [[apocalypse|apocalyptic]] conclusions.

==== Land-based MIRVed ICBMs threaten MAD ====
[[Multiple independently targetable reentry vehicle|MIRVed]] land-based ICBMs are generally considered suitable for a first strike (inherently [[counterforce]]) or a counterforce [[second strike]], due to:
# Their high accuracy (low [[circular error probable]]), compared to submarine-launched ballistic missiles which used to be less accurate, and more prone to defects;
# Their fast response time, compared to bombers which are considered too slow;
# Their ability to carry multiple MIRV warheads at once, useful for destroying a whole missile field or several cities 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 three 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 [[Team B|some]] [[neoconservatives]] to conclude a [[Soviet Union|Soviet]] first strike was being prepared for.{{citation needed|date=August 2021}} 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 [[ICBM]]s are considered destabilizing because they tend to put a premium on striking first. When a missile is MIRVed, it is able to carry many [[warhead]]s (up to eight in existing US missiles, limited by [[New START]], though Trident II is capable of carrying up to 12<ref>{{Cite web |url=http://missilethreat.com/missiles/ugm-133-trident-d-5/ |title=UGM-133 Trident D-5 - Missile ThreatTrident 2 &#124; Missile Threat |access-date=2015-02-18 |archive-url=https://web.archive.org/web/20151027084659/http://missilethreat.com/missiles/ugm-133-trident-d-5/ |archive-date=2015-10-27 |url-status=dead }}</ref>) and deliver them to separate targets. If it is assumed that each side has 100 missiles, with five warheads each, and further that each side has a 95 percent chance of neutralizing the opponent's missiles in their silos by firing two warheads at each silo, then the attacking side can reduce the enemy ICBM force from 100 missiles to about five 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 brought into force, and neither Russia nor the United States ratified the agreement.