Launch on warning

Launch on warning (LOW) is a strategy of nuclear weapon retaliation that gained recognition during the Cold War between the United States and the Soviet Union. With the invention of intercontinental ballistic missiles (ICBMs), launch on warning became an integral part of mutually assured destruction (MAD) theory. Under the strategy, a retaliatory strike is launched upon warning of enemy nuclear attack while its missiles are still in the air and before detonation occurs.

Before the introduction of intercontinental ballistic missiles (ICBMs), the U.S. Strategic Air Command had multiple bombers on patrol at all times like, presumably, its Soviet counterpart. In the event of a nuclear strike by one of the nations, the other nation would order its bombers to fly to the other country and drop their nuclear payload on predetermined targets. In the United States, the bombers were typically either B-47 Stratojets or B-52 Stratofortresses, and there were three major flight routes. Keeping bombers in the air assured that a second strike would be feasible even if the first strike were to impair ground facilities. At the height of the Cold War, the United States had special Boeing EC-135 "Looking Glass" aircraft equipped as control centers for the nuclear arsenal. The battle staff included a general or flag officer who was authorized to order a retaliatory strike if the President could not be contacted.

Launch on warning has its roots in US President Dwight Eisenhower's "Positive Control" strategy but really took shape with the introduction of the Minuteman missile. Since many ICBMs (including the Minuteman) were launched from underground silos, the concern arose that a first strike, by one nation, could destroy the ground launch facilities of the retaliating nation.

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