Stability has become a fundamental concept in nuclear strategy, and a magic formula. Strategic situations are measured by the degree of their stability. Surprise and preemption are valid when they can secure a radical solution to a conflict and establish the superiority of one side. Once a situation of stability has been achieved, the initiation of war by surprise no longer assures any gain or advantage. Conventional strategy dealt with the subject of surprise principally from the operational and tactical point of view, paying less attention to surprise in the initiation of a war. In the past, when war was conducted by standing armies and extensive mobilization was not necessary, surprise at the outset of a war was still possible. Preemptive attack, therefore, is dependent upon the technological sophistication of instrumentation, but instruments are not infallible. Their functioning may be disturbed by mechanical breakdown or by 'electronic warfare' waged by the enemy.