Social Organization. In precontact times age carried some status but the greatest status was held by traditional leaders or big-men ( mumi ), the greatest of whom in the present century was Soni of Tutuguan village. Leadership was achieved through acquiring wealth and renown, which resulted from industriousness, charisma, acumen, diplomacy, and kinship support. Leaders normally acquired wealth in pigs, land, and also wives, through various exchanges, and through forms of redistribution, usually in association with funerary feasts. Other men had various degrees of renown and prestige, but there was no formal ranking system. Women had substantial authority principally in their own productive and ritual areas; women were not recognized as traditional leaders in their own right. In the postwar years, though some men are still recognized as traditional leaders, leadership itself has taken on new forms, as businessmen and politicians have acquired different spheres of operation and feasting has become generally less substantial and significant in everyday life. Many men are often absent from the villages for long periods of time. The economic independence of women has lessened as the cash economy has become more important.
Political Organization. In precontact time Siwai was not a tribal group in any sense other than linguistically. In the prewar years, the administration appointed individuals in each village to liaise with administration officials, but Siwai only became an effective political unit in the 1960s with the establishment of a local government council. Otherwise, Siwai was still divided into seven districts, and it effectively reverted to its former decentralized political organization in the 1970s with the establishment of community governments to replace the local government council. Most villages now have their own councils. Siwai elects two members of the North Solomons Provincial Government and is part of the national South Bougainville constituency.
Social Control. In earlier times, leaders were the principal means of social control and acquired renown partly through their ability to achieve this. In the 1920s, the administration appointed village headmen to assist the administration in achieving law and order; however, except for new offenses, their authority was less than that of traditional leaders. A more modern court system evolved alongside the local Government council but was replaced by more traditional village courts working with community governments. Serious offenses are considered at the provincial level. Traditional leaders now have less ability to achieve social control. Social Control was also achieved by avoidance behavior. Sorcerers also had considerable authority, which is now more often wielded by church leaders.
Conflict. Before the twentieth century there was intermittent feuding and localized warfare within Siwai, and probably occasionally with neighboring language groups. Wars were organized by mumis, but they rarely involved many people, lasted long, caused much loss of life, or covered a wide area. Individual disputes rarely led to open hostility. In the present century, such warfare has ended. There remain divisions within Siwai, marked by the adherence of different districts to the Catholic or the United church, which have occasionally sparked conflicts. More recently, there have been disputes over political issues such as secession and over the closure of the Panguna mine that have led to conflict.