The most important characteristic of the international personality of an entity is its treaty-making power.

The treaty-making power of international governmental organizations is well entrenched in the United Nations practice. The 1986 Vienna Convention on the Law of Treaties between States and International Organizations or between International Organizations confirms that governmental organizations have the capacity to enter into treaties. However, their international personality is confined to their constituent instruments, resolutions, and decisions, which determine the limits of their personality. Thus, the legal personality of international organizations is now an accepted fact. However, unlike states, they do not enjoy unlimited power. Their personality, in fact, can be brought to an end by amending or terminating the constituent instruments.