What distinguishes a treaty from customary law?

A treaty is distinguished by being a formally negotiated agreement between states or international entities that is intended to create specific legal obligations. Treaties typically involve official documentation and must be ratified or accepted by the parties involved, which establishes a binding commitment to adhere to the terms outlined within the treaty.

By contrast, customary law arises from the consistent practice of states accompanied by a belief that such practices are legally obligatory (opinio juris). Customary law does not require formal negotiation or written documentation and develops over time through widespread acceptance and recognition among states.

The correct characterization of treaties emphasizes their formal nature and the structured process through which they are created and implemented, in contrast to the more organic development of customary law.