Security policy has traditionally focused on the threat of deliberate aggression with a clarity and emotional intensity that presumably derives from the far recesses of time. For most of history, it was appropriate to be primarily concerned with intentional aggression since the destruction human beings could inflict on one another had to be consciously organized if it was to occur on a major scale. It is increasingly evident, however, that advanced technology and the sheer magnitude of human activity are generating a different form of threat. Today, an unanticipated chain of spontaneous effects might rival or exceed the destructiveness of intentional war. This sort of accidental war might erupt, ironically, from the military operations designed to protect against the risk of classic aggression itself.
The danger of accidental war was demonstrated in World War I and was recognized in its aftermath. The experience of World War II, however, obscured the lesson and powerfully reinforced the traditional concern of intentional aggression. Over the ensuing decades, as the instruments of warfare acquired capacities for rapid and massive destruction, the military forces that wielded them were configured to deter or to defeat deliberate attack. Precautions were taken to assure that their enormously destructive power would not be employed without legitimate authorization, but those precautions were clearly subordinated to the purpose of deterrence. That effect was achieved and is plausibly credited with preventing at least the largest forms of deliberate aggression, but the accomplishment has enabled a massive accident to occur. Overwhelming deterrence entails some inherent risk of inadvertent catastrophe.
John Steinbruner is the director of the Center for International Security Studies at Maryland.