First strike (nuclear strategy)

In nuclear strategy, a first strike or preemptive strike is a preemptive surprise attack employing overwhelming force. First strike capability is an attacking country's ability to significantly cripple another nuclear power's second strike retaliatory capacity. The preferred methodology is to attack the opponent's strategic nuclear weapon facilities (missile silos, submarine bases, bomber airfields), command and control sites (a decapitation strike), and storage depots first. The strategy is called counterforce.

During the 1950s, first strike strategy required strategic bomber sorties taking place over hours and days. In the 1960s, the deployment of intercontinental ballistic missiles cut the first strike duration to 30 minutes. Also during the Cold War, medium- and intermediate-range ballistic missiles, such as those involved in the Cuban Missile Crisis and Euromissile Crisis, as well as submarine-launched ballistic missiles, reduced the time even further, often below 10 minutes.

Second strike countermeasures to effectively deter first strikes include early warning systems, launch on warning for missile silos, continuous nuclear-capable submarine stealth patrols, and continuous airborne patrols.

First-strike attack, the use of a nuclear first strike capability, was greatly feared during the Cold War between NATO and the Soviet Bloc. At various points, fear of a first strike attack existed on both sides. Misunderstood changes in posture and well understood changes in technology used by either side often led to speculation regarding the enemy's intentions.

In the aftermath of World War II, the leadership of the Soviet Union feared the United States would use its nuclear superiority to initiate a full-scale attack, as from 1945 to 1948 the U.S. was the only state possessing nuclear weapons and until the late 1960s preserved an overwhelming superiority. The USSR countered by rapidly developing their own nuclear weapons, surprising the US with their first test in 1949. In turn, the U.S. countered by developing the vastly more powerful thermonuclear weapon, testing their first hydrogen bomb in 1952 at Ivy Mike, but the USSR quickly countered by testing their own thermonuclear weapons, with a test in 1953 of a semi-thermonuclear weapon of the Sloika design, and in 1956, with the testing of Sakharov's Third Idea – equivalent to the Castle Bravo device. Meanwhile, tensions between the two nations rose as 1956 saw Soviet invasion of Hungary; the U.S. and European nations drew certain conclusions from that event, while in the U.S., a powerful social backlash was afoot, prompted by Senator Joseph McCarthy, the House Un-American Activities Committee, and Julius and Ethel Rosenberg, U.S. citizens executed in 1953 after conviction of espionage. This atmosphere was further inflamed by the 1957 launch of Sputnik, which led to fears of Communists attacking from outer space, as well as concerns that if the Soviets could launch a device into orbit, they could equally cause a device to re-enter the atmosphere and impact any part of the planet. John F. Kennedy capitalized on this situation by emphasizing the bomber gap and the missile gap, areas in which the Soviets were (inaccurately) perceived as leading the United States, while heated Soviet rhetoric added to political pressure. The 1960 U-2 incident, involving Francis Gary Powers, as well as the Berlin Crisis, along with the test of the Tsar Bomba, escalated tensions still further.

This escalating situation came to a head with the Cuban Missile Crisis of 1962. The arrival of Soviet missiles in Cuba was conducted by the Soviets on the rationale that the US already had nuclear missiles stationed in Turkey, as well as the desire by Fidel Castro to increase his power, his freedom of action, and to protect his government from US invasion, such as had been attempted during the Bay of Pigs Invasion in April 1961. During the crisis, Fidel Castro wrote Khrushchev a letter about the prospect that the "imperialists" would be "extremely dangerous" if they responded militarily to the Soviet stationing of nuclear missiles aimed at US territory, less than 90 miles away in Cuba. The following quotation from the letter suggests that Castro was calling for a Soviet first strike against the US if it responded militarily to the placement of nuclear missiles aimed at the US in Cuba:

If the second variant takes place and the imperialists invade Cuba with the aim of occupying it, the dangers of their aggressive policy are so great that after such an invasion the Soviet Union must never allow circumstances in which the imperialists could carry out a nuclear first strike against it. I tell you this because I believe that the imperialists' aggressiveness makes them extremely dangerous, and that if they manage to carry out an invasion of Cuba—a brutal act in violation of universal and moral law—then that would be the moment to eliminate this danger forever, in an act of the most legitimate self-defense. However harsh and terrible the solution, there would be no other.

The Cuban Missile Crisis resulted in Nikita Khrushchev publicly agreeing to remove the missiles from Cuba, while John F. Kennedy secretly agreed to remove his country's missiles from Turkey. Both sides in the Cold War realized how close they came to nuclear war over Cuba, and decided to seek a reduction of tensions, resulting in US-Soviet détente for most of the 1960s and 1970s.