Perhaps counterintuitively, an important focus of nuclear strategy has been determining how to prevent and deter their use, a crucial part of mutually assured destruction.
The doctrine of mutual assured destruction (MAD) assumes that a nuclear deterrent force must be credible and survivable.
In the late 1940s and 1950s as the Cold War developed, the United States and Soviet Union pursued multiple delivery methods and platforms to deliver nuclear weapons.
It seemed unthinkable to respond to a Soviet/Warsaw Pact incursion into Western Europe with strategic nuclear weapons, inviting a catastrophic exchange.
Other technologies were so-called "suppressed radiation devices," which produced mostly blast with little radioactivity, making them much like conventional explosives, but with much more energy.