Of Indonesia's population, 87.1 percent identified themselves as Muslim in 1980. This number was down from 95 percent in 1955. The figures for 1985 and 1990 were not released by the government's Central Bureau of Statistics (BPS), suggesting a further decline that would fuel the fires of Muslim indignation over Christianization and secularization under the New Order. Nevertheless, Indonesia was still the largest Muslim nation in the world in the early 1990s, united with the universal Islamic community (ummah) not only in the profession of faith but also in adherence to Islamic law (see Religion and Worldview , ch. 2). The appeal of Islam was not weakened when it was supplanted by modern secular nationalism as the basis for the independent Indonesian state. In fact, given the prominence of Islamic proselytization and reinvigoration, the people's desire to maintain Islamic institutions and moral values arguably was at an all-time high in Indonesia. There was, however, a separation between Islam as a cultural value system and Islam as a political movement.

Islam in Indonesia is not monolithic. The majority of Indonesia's nominal or statistical Muslims, abangan (see Glossary), are, to varying degrees of self-awareness, believers in kebatinan (see Islam , ch. 2). Orthodox Islam is, in fact, a minority religion, and the term often used to describe the orthodox believer is santri (see Glossary). A rough measurement of the appeal of orthodox Islam is the size of the electorate supporting explicitly Muslim political parties, which in the general elections of 1977 and 1982 approached 30 percent. In a pluralistic setting, such numbers might be expected to represent political strength. This correlation would exist in Indonesia if Indonesian Islam spoke with a single, unified voice. In the early 1990s it did not. The santri consisted of both traditionalists and modernists, traditionalists seeking to defend a conservatively devout way of life, protecting orthodoxy as much as possible from the demands of the modern state, and modernists striving to adapt Indonesian Islam to the requirements of the modern world.

The principal organization reflecting the traditionalist outlook was Nahdatul Ulama (literally, "revival of the religious teachers," but commonly referred to as the Muslim Scholars' League) founded in 1926. Nahdatul Ulama had its roots in the traditional rural Islamic schools (pesantren) of Central and East Java. Claiming more than 30 million members, in 1992 Nahdatul Ulama was the largest Muslim organization in Indonesia. Although its rural teachers and adherents reflected its traditional orientation, it was led into the 1990s by Abdurrahman Wahid, grandson of Nahdatul Ulama's founder, a "democrat" with a non-exclusive vision of Islam and the state. Modernist, or reformist, Islam in Indonesia was85c as best exemplified by the Muhammadiyah (followers of Muhammad), founded in 1912 when the spirit of the Muslim reform movement begun in Egypt in the early 1900s reached Southeast Asia. In addition to modernizing Islam, the reformists sought to purify (critics argue Arabize) Indonesian Islam.

Both santri streams found formal political expression in the postindependence multiparty system. The Consultative Council of Indonesian Muslims (Masyumi) was the main political vehicle for the modernists. However, its activities were inhibited by the PRRI-Permesta regional rebellions between 1957 and 1962 and the party was banned in 1959. Nahdatul Ulama competed in the politics of the 1950s, and seeking to capitalize on Masyumi's banning, collaborated with Sukarno in the hope of winning patronage and followers. Nahdatul Ulama also hoped to stop the seemingly inexorable advance of the secular left under the leadership of the PKI. Although organized Islamic political parties in the New Order were prohibited from advancing an explicitly Islamic message, traditional systems of communication within the community of believers, including instruction in Islamic schools and mosque sermons, passed judgments on politics and politicians.

Data as of November 1992