Second strike In nuclear strategy , a second - strike capability is a country ' s assured ability to respond to a nuclear attack with powerful nuclear retaliation against the attacker . To have such an ability ( and to convince an opponent of its viability ) is considered vital in nuclear deterrence , as otherwise the other side might be tempted to try to win a nuclear war in one massive first strike against its opponent ' s own nuclear forces . Theory . The possession of second - strike capabilities counters a first - strike nuclear threat and can support a no first use nuclear strategy . Reciprocal second - strike capabilities usually cause a mutual assured destruction defence strategy , though one side may have a lower level minimal deterrence response . Second - strike capabilities can be further strengthened by implementing fail - deadly mechanisms . These mechanisms create a threshold and guaranteed consequences if that threshold is breached . For instance , a threshold may be for an allied nation to not be attacked . If a rival nation then breaches this threshold by attacking the allied nation , then the predetermined consequences for this action go into effect . These predetermined consequences could include a wide range of responses , including a retaliatory nuclear second strike . Implementation . The crucial goal in maintaining second - strike capabilities is preventing first - strike attacks from taking out a nation ' s nuclear arsenal , allowing for nuclear retaliation to be carried out . The nuclear triad is a way for countries to diversify their nuclear arsenals in order to better ensure second strike capability . Submarine - launched ballistic missile s are the traditional , but very expensive , method of providing a second strike capability , though it needs to be supported by a reliable method of identifying who the attacker is . Using SLBMs as a second strike capability has a serious problem , because in retaliation for a submarine - launched ICBM , the wrong country could be targeted , and can cause a conflict to escalate . However , implementation of second - strikes are crucial to deter a first strike . Countries with nuclear weapons make it their primary purpose to convince their opponents that a first strike is not worth facing a second strike . Such countries have many diverse launch mechanisms , prepared responses to various nuclear attack scenarios , launch mechanisms in many different areas of the country , and underground launch facilities that are specifically designed to withstand a nuclear attack . Some nuclear missiles are located near borders of armed countries in order to dissuade attackers ; an attack on these sites would likely start a war against multiple countries at once . Launch on warning is a strategy of nuclear weapon retaliation that gained recognition during the Cold War between the United States and the Soviet Union . In addition to the nuclear triad , nations deploy an early warning system that detects incoming nuclear missiles . This gives that nation the capability and option to launch a retaliatory second strike before the incoming nuclear first strike hits any of its targets . This is another method of solidifying second - strike capabilities and deterring a first strike from another nuclear power . History . As early as 1940 , science fiction writer Robert A . Heinlein wrote " Solution Unsatisfactory " in which he described a nuclear arms race between the United States and the Soviet Union . In one episode , the US cabinet discusses the scenario of a Soviet surprise attack in which American cities would be destroyed , but the US armed forces would survive and launch a counter - attack .