Sison's dictums were evident in the party's early development. On the theory that the Huks were defeated because their uprising was localized, the CPP emphasized expansion to other regions of Luzon, and to other islands. After several devastating routs by concentrated AFP attacks, in 1974 the NPA abandoned its early attempts to form Chinese-style base areas. From the CPP's birthplace in Central Luzon, guerrilla cadres established operations in remote areas of Northern Luzon, the Bicol Peninsula, Samar Island, and on the southern island of Mindanao. In each of these impoverished areas, the NPA undertook to support local residents in disputes with the central government, local military and civilian officials, and landlords. In most areas, the communists were able to take advantage of peasant unrest over land issues by embracing the theme of land reform.

Government initiatives did little to check the slow, steady growth of the NPA in the 1970s. Sison and NPA chief Bernabe Buscayno, alias Commander Dante, were arrested, and more than a dozen CPP and NPA leaders were captured or killed during 1976 and 1977. The government also mounted major anti-insurgency campaigns in Northern Luzon and elsewhere. Still, the communists continued to broaden their base of popular support, expand the geographical reach of the movement, and escalate their attacks on military and government targets. Several factors helped the communists gain support: the NPA's decentralized organization, which granted local commanders wide autonomy Philippine geography, which prevented easy access to remote rebel-dominated areas the armed forces' preoccupation with the Moro insurgency and the continued appeal of the insurgents' pledges to solve specific grievances against the government and provide a better life for discontented Filipinos.

In 1983 Philippine officials estimated that the communists exercised substantial control over 2 to 3 percent of the nation's villages and that the NPA fielded some 6,000 full-time guerrillas. The insurgency grew rapidly after that year, largely as a result of growing political turmoil and increasing discontent with the Marcos government. By 1986, when Aquino came to power, approximately 22,500 NPA fighters were operating throughout nearly all the country's provinces. Equally important, some 20 percent of the Philippines' 40,000 villages were influenced by the communists. Although they admitted that they were not yet in a position to bring down the government, CPP leaders calculated that they were in the final phase of the "strategic defensive" and would soon be able to fight the government to a draw and take the offensive.

The overthrow of Marcos, however, threw the communist movement into disarray. The former president's unpopularity was the party's best recruiting theme. Strategic errors added to the communists' woes. The CPP's call for a boycott of the 1986 presidential election was overwhelmingly rejected by Filipinos and by many of the communists' local political organs. Party leaders later confessed that the strategy was a major blunder thae22 hat left the insurgents with no role in the change of government. The CPP's chairman, Rodolfo Salas, resigned in 1986 in the midst of an unprecedented strategic debate within the communist ranks. Many party cadres called for a conciliatory policy toward the new and popular Aquino government, and for open political participation. Initially the CPP adopted a policy of "critical collaboration" with the Aquino administration, but after the lapse of the sixty-day cease-fire in February 1987, the NPA resumed all-out armed attacks. In 1987, after intense and prolonged debate, the party's executive committee confirmed the primacy of the armed struggle and renewed the CPP's commitment to a protracted people's war.

A series of setbacks challenged the communists through the end of the 1980s. The advent of a popular president especially hurt CPP support among the Philippine middle class, students, labor, and other mostly urban segments of society. Recruiting suffered, as did domestic financial support for the guerrillas. Villages in areas largely controlled by the NPA failed to support CPP-backed candidates in the May 1987 congressional elections. The government also succeeded in capturing a number of top CPP and NPA leaders, particularly in 1987 and 1988. Among them were Rodolfo Salas, the former party chairman, and Romulo Kintanar, the NPA chief. Kintanar, however, escaped from prison only months after his 1988 arrest. One result of the repeated roundups of key leaders was a series of bloody internal party purges during 1987 and 1988 rebels suspected of being government informers were executed or expelled. Philippine military leaders publicized widely the mass graves of suspected penetration agents. Popular support for the insurgents waned, and rebel morale was devastated. Mindanao, long an NPA stronghold, was especially hard hit by the loss of up to one-half of insurgent cadres.

By the end of the 1980s, NPA strength had begun to decline. According to government figures, full-time guerrilla strength was 24,000 to 26,000 in 1988, the year that Aquino said would be seen as the turning point in the government's counterinsurgency effort. The NPA was then operating in sixty of the nation's seventy-three provinces and claimed a following of some 500,000 Filipinos. By 1991, the government estimated that insurgent strength had fallen to 18,000 to 23,000 guerrillas. Still, the military believed that the rebels exercised considerable control over more than 18 percent of the Philippines' roughly 42,000 villages, and around 30,000 Filipinos were thought to be CPP members. (Other estimates of rebel strength and influence varied widely one unofficial source placed NPA strength at 34,000.)

Data as of June 1991