International Law-Making

Law Without a Legislature

International law is fundamentally different from domestic law because there is no world legislature. No body of elected representatives passes laws that bind all nations. Instead, international law emerges from three main sources: treaties (agreements between states), customary international law (practices so widespread and consistent that they become legally binding), and general principles of law recognized by civilized nations.

This means international law-making is a process of negotiation and consent rather than majority rule. A treaty only binds the states that ratify it. Customary law requires widespread and consistent state practice plus a belief that the practice is legally required (opinio juris). This consent-based system reflects the principle of state sovereignty — the idea that no authority stands above the nation-state.

How Treaties Are Made

Treaty-making follows a general sequence: negotiation, signature, ratification, and entry into force. Negotiation can take years — the UN Convention on the Law of the Sea took nine years of conferences (1973-1982). Signature signals a state's intent to be bound but is not legally binding. Ratification is the formal act by which a state consents to be bound, usually requiring domestic legislative approval. A treaty enters into force when a specified number of states have ratified it.

The gap between signature and ratification can be enormous. The United States signed the Convention on the Rights of the Child in 1995 but has never ratified it — making it the only UN member state that is not a party. Some states sign treaties with no intention of ratifying, using signature as a diplomatic gesture. Others ratify but attach 'reservations' that exempt them from specific provisions, creating a patchwork of obligations.

International Organizations as Law-Makers

The UN General Assembly cannot pass binding legislation (its resolutions are recommendations), but it can initiate treaty processes and its declarations can crystallize customary law. The UN Security Council is different — its resolutions under Chapter VII are binding on all UN member states. When the Security Council imposed sanctions on North Korea, those were legally binding obligations, not suggestions.

Specialized agencies also create binding international law. The International Civil Aviation Organization sets standards for air safety. The World Health Organization issues International Health Regulations. The International Maritime Organization regulates shipping. These technical bodies produce volumes of binding international rules that most people never hear about but that govern everything from airplane maintenance to pandemic response protocols.

Worked Example: The Life Cycle of the Paris Agreement

The Paris Agreement on climate change shows every stage of treaty-making — including the crucial gap between signing and being legally bound.

• Negotiation: Diplomats from nearly 200 states negotiated the text at the COP21 conference, adopting it on December 12, 2015.
• Signature: The agreement opened for signature on April 22, 2016 (Earth Day); more than 170 states signed on the first day, signaling their intent to join.
• Ratification and entry into force: Signature alone was not enough. The treaty required ratification by at least 55 countries representing at least 55% of global emissions. Once that double threshold was met, it entered into force on November 4, 2016.
• Domestic variation: The United States joined through executive action rather than Senate ratification — which is precisely why a later administration was able to withdraw in 2020, and the next to rejoin in 2021.

The example illustrates the core rule of international law: a state is bound only when it consents through ratification, and how it consents depends entirely on its own constitution.