How did tapu help protect people and objects believed to possess mana?

In Polynesian culture, tapu (prohibitions or taboos) served as a vital regulatory system designed to protect mana—a sacred supernatural power believed to reside in people, objects, and places.1

Tapu helped preserve this power in several ways:

• Preventing Defilement: Many tapu were established to prevent behaviors that could sap or nullify mana. For example, actions such as stepping over a person’s legs or passing a hand over a high-ranking person's head were prohibited because they were believed to diminish that individual's power.1
• Managing Competing Powers: Tapu ensured the mutual protection of different sources of mana. In the Marquesas, for instance, women were prohibited from entering canoes because their mana and the mana of the vessel were considered incompatible.1
• Maintaining Sacred Boundaries: Because buildings, tools, and tracts of land could possess mana, tapu restricted access to these areas or objects to prevent them from becoming profane through contact with ordinary people. If an object was inadvertently touched or stepped over, it was often discarded.1
• Ritual Purification: For those preparing for hazardous tasks like war, tapu mandated periods of seclusion and specific dietary restrictions to protect their personal power from being defiled.1

Violations of these prohibitions were believed to result in supernatural punishment, such as illness or bad luck, and in cases of major violations, the penalty was often death.1