Since the onset of the Cold War, and particularly after both superpowers began to amass large arsenals of nuclear weapons, military planners in the East and West have encouraged efforts to develop defenses against nuclear attacks. Both sides have made effective use of “passive” defenses, such as the hardening and dispersal of weapons systems likely to be the prime targets of a preemptive strike and the provision of shelters for command authorities and vital communications centers. Both sides have also tried, but with far less success, to develop “active” defenses, but against the varied and daunting challenge of modern strategic systems, all such efforts so far have been largely in vain, even though they have been undertaken at considerable expense and with great technical sophistication. The main reason is that every advance in active defense has been offset by compensatory improvements in offensive forces.
The IAEA’s Right to Visit Sites Accused of Developing Nuclear Weapons Systems: The Parchin Facility in Iran