Despite the nation's status as a major world power, Japan eschewed responsibility for regional defense. Having renounced war, the possession of war potential, the right of belligerency, and the possession of nuclear weaponry, it held the view that it should possess only the minimum defense necessary to face external threats. Within those limits, the Self-Defense Forces Law of 1954 provides the basis from which various formulations of SDF missions have been derived. The law states that ground, maritime, and air forces are to preserve the peace and independence of the nation and to maintain national security by conducting operations on land, at sea, and in the air to defend the nation against direct and indirect aggression.
The general framework through which these missions are to be accomplished is set forth in the Basic Policy for National Defense adopted by the cabinet in 1957; it remains in force. According to this document, the nation's security would be achieved by supporting the United Nations (UN) and promoting international cooperation, by stabilizing domestic affairs and enhancing public welfare, by gradually developing an effective self-defense capability, and by dealing with external aggression on the basis of Japan-United States security arrangements, pending the effective functioning of the UN.
The very general terms in which military missions are couched left specifics open to wide interpretation and prompted the criticism that the nation did not possess a military strategy. In the 1976 National Defense Program Outline, the cabinet sought to define missions more specifically by setting guidelines for the nation's readiness, including specific criteria for the maintenance and operation of the SDF. Under these guidelines, in cases of limited and small-scale attack, Japanese forces would respond promptly to control the situation. If enemy forces attacked in greater strength than Japan could counter alone, the SDF would engage the attacker until the United States could come to its aid. Against nuclear threat, Japan would rely on the nuclear deterrence of the United States. To accomplish its missions, the SDF would maintain surveillance, be prepared to respond to direct and indirect attacks, be capable of providing command, communication, logistics, and training support, and be available to aid in disaster relief.
The outline specified quotas of personnel and equipment for each force that were deemed necessary to meet its tasks. Particular elements of each force's mission were also identified. The GSDF was to defend against ground invasion and threats to internal security, be able to deploy to any part of the nation, and protect the bases of all three services of the Self-Defense Forces. The MSDF was to meet invasion by sea, sweep mines, patrol and survey the surrounding waters, and guard and defend coastal waters, ports, bays, and major straits. The ASDF was to render aircraft and missile interceptor capability, provide support fighter units for maritime and ground operations, supply air reconnaissance and air transport for all forces, and maintain airborne and stationary early warning units.
The Mid-Term Defense Estimate for FY 1986 through FY 1990 envisioned a modernized SDF with an expanded role. While maintaining Japan-United States security arrangements and the exclusively defensive policy mandated by the constitution, this program undertook moderate improvements in Japanese defense capabilities. Among its specific objectives were bettering air defense by improving and modernizing interceptor-fighter aircraft and surface-to-air missiles, improving antisubmarine warfare capability with additional destroyers and fixed-wing antisubmarine patrol aircraft, and upgrading intelligence, reconnaissance, and command, control, and communications. Most of the goals of this program were met, and the goals of the Mid-Term Defense Estimate for FY 1991 through FY 1995, although building on the early progam, were considerably scaled back.
The SDF disaster relief role is defined in Article 83 of the Self-Defense Forces Law of 1954, requiring units to respond to calls for assistance from prefectural governors to aid in fire fighting, earthquake disasters, searches for missing persons, rescues, and reinforcement of embankments and levees in the event of flooding. The SDF has not been used in police actions, nor is it likely to be assigned any internal security tasks in the future.
In June 1992, the National Diet passed a UN Peacekeeping Cooperation Law which permitted the SDF to participate in UN medical, refugee aid, transportation, infrastructural repair, election-monitoring, and policing operations under strictly limited conditions (see The Legislature , ch. 6). This law was used in 1992- 93 to authorize the deployment of 600 SDF and seventy-five police personnel for UN engineering and election-monitoring projects in Cambodia and again in the spring of 1993 to send fifty-three persons to participate in peacekeeping operations in Mozambique.
Data as of January 1994