In the years following World War II, a new kind of threat surfaced. The United States developed intercontinental ballistic missiles (ICBM) that could carry nuclear warheads and strike targets thousands of miles away. The new weapon posed such a grave risk that it became the basis for a whole school of military strategy known as deterrence, in which the threat of massive retaliation was meant to keep both countries from attacking each other in any circumstance.
For years, the United States and Soviet Union constructed vast defensive systems to guard against each other’s bombers and ICBMs. The Americans put layered defenses in place that would intercept Soviet bombers and destroy incoming ICBMs before they reached their target. The Soviets responded with the development of a submarine fleet that would allow them to get close to US and British coastlines without being detected, decreasing the warning time to less than half an hour.
The nuclear taboo has since been lifted, and nations have acquired their own arsenals of weapons. The fear that the smallest mistake could lead to nuclear destruction remains strong, as do concerns about terrorists gaining access to these weapons. In addition, scientific modeling shows that the effects of an all-out nuclear war – including destroying cities and killing millions, as well as a “nuclear winter” caused by the smoke from burning buildings and the dust from ground bursts obscuring the sun’s rays — could be catastrophic in terms of human casualties, environmental damage, and the loss of life as we know it.