Education efforts on the effects of nuclear weapons proceeded with stops-and-starts in the US due to competing alternatives. In a once classified, 1950s era, US war game that looked at varying levels of war escalation, warning and pre-emptive attacks in the late 1950s early 1960s, it was estimated that approximately 27 million US citizens would have been saved with civil defense education. At the time however the cost of a full-scale civil defense program was regarded as lesser in effectiveness, in cost-benefit analysis than a ballistic missile defense (Nike Zeus) system, and as the Soviet adversary was believed to be rapidly increasing their nuclear stockpile, the efficacy of both would begin to enter a diminishing returns trend. When more became known about the cost and limitations of the Nike Zeus system, in the early 1960s the head of the department of defense under president John F. Kennedy,