How did nuclear weapons and intercontinental missiles increase the importance of early warning?

The advent of nuclear weapons and intercontinental ballistic missiles (ICBMs) fundamentally transformed military strategy, making early warning systems a critical priority for national security.12

The importance of these systems increased due to several key factors:

• Extreme Destructiveness and Speed: Unlike conventional warfare, nuclear weapons offered the potential for overwhelming destruction in a single strike. As flight times for ICBMs between superpowers shrank to less than 35 minutes, the window for decision-makers to react narrowed significantly.13
• Vulnerability of Strategic Assets: Land-based ICBMs were vulnerable to preemptive nuclear attacks, leading to the development of "hardened" silos and complex command-and-control installations. Early warning was essential to ensure these forces could be utilized or protected before being destroyed.4
• Strategic Deterrence: Under doctrines like mutual assured destruction, the primary goal of military establishments shifted toward preventing conflict. Reliable warning systems were necessary to verify enemy actions, thereby maintaining the stability of deterrence and preventing accidental or miscalculated escalations.15

To address these challenges, nations deployed sophisticated warning systems, including ground-based radars, over-the-horizon radars, and satellite-borne infrared detectors, to provide the tactical warning required to respond to imminent threats.42