PD 41 was the result of an “interagency study of U.S. civil defense policy, directed by the President in September 1977…conducted over a period of about a year…[drawing upon] studies of Soviet and U.S. civil defense programs… Among the specific questions addressed were: ‘What is the role of civil defense in strategic policy?’ ‘Can civil defense make a significant difference in the outcome of a nuclear exchange?’ ‘What civil defense measures would be most useful?’ and finally, ‘If a role is identified, what should it be?’ Hence, the study looked not only at whether civil defense would make a difference in nuclear war, but also at whether it could play a role in a preattack crisis. “The study examined a range of CD program options for the United States, and was presented to the Policy Review Committee of the NSC and then to the President. The options were essentially the same as those analyzed in…[an] earlier study for the Secretary of Defense: 91) essentially no program; (2) the current program; (3) a program providing for evacuating the population of larger U.S. cities and other risk areas, should time permit during a period of strategic warning resulting from an international crisis; and (4) a short warning time program to protect the population in-place, including construction of blast shelters in cities. “In September 1978, the President directed in Presidential Decision (PD) 41 that a new civil defense policy be implemented along the following lines: (1) That the United States civil defense program should enhance the survivability of the American people and its leadership in the event of nuclear war, thereby improving the basis for eventual recovery, as well as reducing vulnerability to a major Soviet attack; (2) That the program should enhance deterrence and stability, and contribute to perceptions of the overall U.S./Soviet strategic balance and to crisis stability, and also reduce the possibility that the Soviets could coerce us in times of increased tension; (3) That the CD policy not suggest any change in the U.S. policy of relying on strategic nuclear forces as the preponderant factor in maintaining deterrence; and, (4) That the program include planning for population relocation during times of international crisis as well as be adaptable to help deal with natural disasters and other peacetime emergencies”. (Chipman, CD for the 1980’s, 1979, pp. 24-25)