The PLA played a complex political role during the Cultural Revolution (see The Cultural Revolution Decade, 1966-76 , ch. 1). From 1966 to 1968, military training, conscription and demobilization, and political education virtually ceased as the PLA was ordered first to help promote the Cultural Revolution and then to reestablish order and authority. Although the Cultural Revolution initially developed separately in the PLA and in the party apparatus, the PLA, under the leadership of its radical leftist leader, Lin Biao, soon became deeply involved in civilian affairs. In early 1967 the military high command was purged, and regional military forces were instructed to maintain order, establish military control, and support the revolutionary left. Because many regional-force commanders supported conservative party and government officials rather than radical mass organizations, many provincial-level military leaders were purged or transferred, and Beijing ordered several main-force units to take over the duties of the regional-force units. In the summer of 1967, regional military organizations came under leftist attack, Red Guard factions obtained weapons, and violence escalated. By September the central authorities had called off the attack on the PLA, but factional rivalries between regional- and main-force units persisted. Violence among rival mass organizations, often backed by different PLA units, continued in the first half of 1968 and delayed the formation of revolutionary committees, which were to replace traditional government and party organizations. In July 1968 Mao abolished the Red Guards and ordered the PLA to impose revolutionary committees wherever such bodies previously had not been established.

Worries over military factionalism caused the leadership to curtail the Cultural Revolution and to initiate a policy of rotating military commanders and units. The Soviet invasion of Czechoslovakia, the enunciation of the Brezhnev Doctrine, the Soviet military buildup in its Far Eastern theater, and Sino-Soviet border clashes in the spring of 1969 brought about a renewed emphasis on some of the PLA's traditional military roles. In 1969 Lin Biao launched an extensive "war preparations" campaign military training was resumed, and military procurement, which had suffered in the first years of the Cultural Revolution, rose dramatically. Military preparedness was further advanced along China's frontiers and particularly the Sino-Soviet border when the thirteen military regions were reorganized into eleven in 1970.

The PLA emerged from the more violent phase of the Cultural Revolution deeply involved in civilian politics and administration. It had committed 2 million troops to political activities and reportedly suffered hundreds of thousands of casualties. Regional military forces were almost completely absorbed in political work. PLA units did not withdraw fully from these duties until 1974. Following the sudden death of Lin Biao in 1971, the military began to disengage from 800 m politics, and civilian control over the PLA was reasserted. Lin's supporters in the PLA were purged, leaving some high-level positions in the PLA unfilled for several years. PLA officers who had dominated provincial-level and local party and government bodies resigned from those posts in 1973 and 1974. Military region commanders were reshuffled, and some purged military leaders were rehabilitated. Military representation in the national-level political organizations, following an all-time high at the Ninth National Party Congress in 1969, declined sharply at the Tenth National Party Congress in 1973 (see The Cultural Revolution Decade, 1966-76 , ch. 1).

Along with the reassertion of civilian control over the military and the return to military duties came a shift of resources away from the defense sector. Defense procurement dropped by 20 percent in 1971 and shifted from aircraft production and intercontinental ballistic missile development to the modernization of the ground forces and medium-range ballistic missile and intermediate-range ballistic missile development.

Data as of July 1987