One of the defining characteristics of an Intergovernmental Organisation is a ____________.

Peacekeeping force
Treaty
Declaration
Security Council

Treaty

One of the defining characteristics of an Intergovernmental Organization (IGO) is a Treaty.

The correct answer is "Treaty."

To arrive at this answer, we need to understand what an intergovernmental organization (IGO) is and its characteristics.

An intergovernmental organization is an institution created by a formal agreement among sovereign states to cooperate and work together on common goals or issues. These organizations are usually established through the signing and ratification of a treaty, which serves as the foundation and legal framework for their existence and operations.

The key characteristic of an IGO is the treaty that establishes its authority, structure, and purpose. A treaty is a formal and legally binding agreement between two or more states. It sets out the rights and obligations of the member states, defines the organization's functions and powers, and governs its decision-making processes. In the case of an intergovernmental organization, the treaty defines the overall objectives of the organization and provides the framework for cooperation among member states.

Therefore, among the options provided, the correct characteristic of an intergovernmental organization is a "Treaty."