Which of the following best defines an intergovernmental organization (IGO)?

The definition of an intergovernmental organization (IGO) is best captured by the concept of an organization composed primarily of sovereign states, established by a treaty. IGOs are formal institutions that serve multiple purposes in international relations, including cooperation on common issues such as security, trade, health, and the environment. Their formation through treaties signifies a legal agreement among states to collaborate on defined matters, which is a foundational aspect of how IGOs operate.

The elements of sovereignty and mutual consent to collaborate in specific areas distinguish IGOs from other types of organizations. This framework enables member states to engage in dialogue, negotiate policies, and make collective decisions that can influence international norms and behaviors. Examples of IGOs include the United Nations, NATO, and the World Trade Organization, all of which are made up of member states that have agreed to work together for common goals.

The other options do not accurately depict the structure or purpose of IGOs. An organization focused solely on humanitarian aid does not encompass the broader range of issues that IGOs typically address. Organizations that are mainly composed of non-governmental entities are categorized differently; they are classified as non-governmental organizations (NGOs), which operate independently from governments and often focus on specific missions rather than intergovernmental cooperation