Political organisation in social and cultural anthropology refers to the ways in which human societies regulate power, authority, decision-making, social order, and the distribution of resources. Anthropologists study political organisation to understand how people maintain social control, resolve conflicts, exercise leadership, and establish relationships between individuals and groups. Political organisation exists in all societies, although its forms vary greatly according to population size, economic system, social structure, history, and cultural traditions. Anthropologists have traditionally classified political organisation into four broad types: bands, tribes, chiefdoms, and states. These categories help in understanding differences in political authority and social complexity, although actual societies may not always fit neatly into one category. A band is generally a small, relatively egalitarian political unit found among hunting and gathering communities. It consists of a limited number of families or households connected through kinship, marriage, and cooperation. Leadership is usually informal and temporary. Individuals may possess influence because of their experience, hunting ability, knowledge, age, or personal qualities, but they generally do not have coercive power over others. Decisions are often made through discussion and consensus. Social pressure,